The WorldCalculate library

Home Purchase Loan and Amortization Estimate a fixed monthly principal-and-interest payment from a home or purchase price minus a down payment, and inspect every payment in the amortization schedule. Retirement Contribution Forecast Project an accumulation balance from existing retirement savings and an annual contribution budget deposited in twelve monthly installments, with a yearly growth table. Monthly Savings Growth Forecast how a starting balance and regular monthly-end deposits accumulate, with contributions, interest, and year-by-year balances shown separately. Recurring Investment Growth Compare hypothetical investment accumulation scenarios using an annual investing budget split into monthly-end contributions, including constant negative-return scenarios. Fixed-Payment Debt Payoff Find the number of monthly payments needed to clear a balance, including total interest and a smaller final payment, while rejecting payments that cannot reduce the debt. Inflation and Purchasing Power Distinguish the future amount needed to match today's cost from the purchasing power of an unchanged future amount, using your own constant inflation or deflation scenario. Lump-Sum Compound Interest Grow a single initial amount with monthly compounding and no further deposits, showing the yearly balance and the share attributable to interest. Simple Interest and Final Balance Calculate interest charged or earned only on the original principal over an explicitly stated number of years, including fractional-year periods without compounding. Monthly Deposit for a Savings Target Solve for the monthly-end contribution needed to reach a chosen future balance after accounting for existing savings and hypothetical monthly-compounded interest. Gross Hourly and Salary Equivalents Convert an hourly wage or annual gross salary into annual, monthly-average, paid-week, and hourly equivalents using your own paid-hours and paid-weeks assumptions. Compound Annual Growth Rate Convert a beginning value, ending value, and elapsed years into a smoothed annual growth rate, including declines and total losses when there are no intervening cash flows. APR and Effective Annual Rate Converter Convert between nominal APR with compounding frequency and the effective annual rate. Present Value of a Future Sum Discount a future amount back to today at a constant annual rate. Future Value of Annuity Growth of equal end-of-period payments at a constant rate. Present Value of Annuity Today's value of equal future payments, e.g. a loan's principal. Rule of 72 Doubling Estimator Mental-math estimate of years to double money at a fixed rate. Net Present Value (NPV) Value of a cash-flow series with the first flow at time zero. Basic Bond Price Fair price of an annual-coupon bond from yield to maturity. Gordon Growth Stock Value Constant-growth dividend discount value with sanity checks. Emergency Fund Target Cash buffer from monthly essential spending and chosen months of cover. Real Return (Fisher Equation) Inflation-adjusted return from nominal return and inflation. Generic Loan Payment Calculator Estimate periodic payment, total repayment, and interest for a fixed-rate amortizing loan. Altman Z-Score Calculator Estimate a company’s Altman Z-score from five accounting ratios used in a bounded financial-distress screening model. After-Tax Cost of Debt Calculator Estimate the after-tax cost of debt from a nominal borrowing rate and an entered tax rate. Annualized Return Calculator Convert an initial value, final value, and holding period into a compound annualized return. Cash Flow to Debt Ratio Calculator Compare operating cash flow with total debt as a percentage-based coverage ratio. Free Cash Flow Calculator Estimate free cash flow by subtracting capital expenditures from operating cash flow. Price-to-Cash-Flow Ratio Calculator Calculate a price-to-cash-flow multiple from share price and cash flow per share. Fibonacci Retracement Level Calculator Calculate common retracement levels between a selected low and high price. Average Collection Period Calculator Estimate days to collect receivables from average accounts receivable and net credit sales. Asset Appreciation Calculator Calculate absolute and percentage appreciation between an initial value and a current value. Basis Point Converter Convert a percentage-point change into basis points and a decimal rate change. Beta from Covariance Calculator Calculate a simple beta coefficient from covariance with the market and market variance. Price Elasticity of Supply Calculator Calculate midpoint price elasticity of supply from two price and quantity observations. Bond Current Yield Calculator Calculate a bond’s current yield from annual coupon income and its current market price. Bank Reconciliation Adjusted Balance Calculator Calculate an adjusted bank balance from deposits in transit, outstanding payments, fees, interest, and a signed other adjustment. Operating Profit Calculator Calculate operating profit and margin from revenue, cost of goods sold, operating expenses, and net other income or expense. Cash Flow Accrual Ratio Calculator Calculate a simple accrual ratio from net income, operating cash flow, and average total assets. Annual Pay Calculator Convert pay per period into annual pay and a monthly equivalent using a selected number of pay periods and annual bonus. Average Propensity to Consume Calculator Calculate the share of disposable income spent on consumption and the complementary saving share. Additional Funds Needed Calculator Estimate additional external financing from projected sales growth, asset intensity, spontaneous liabilities, retained profit, and payout. Annual Salary to Hourly Equivalent Calculator Convert annual salary into monthly, weekly, and hourly equivalents using work weeks and hours per week. Real Estate Capitalization Rate Calculator Calculate capitalization rate and implied property value from net operating income and a selected cap rate. Simple Child Budget Calculator Estimate a planning total from selected recurring child-related cost categories and a yearly one-time cost. Straight-Line Appliance Depreciation Calculator Estimate straight-line annual depreciation, current book value, and remaining life for an appliance or equipment purchase. Cake Pricing and Margin Calculator Estimate a cake price from ingredient cost, labor, overhead, and a selected markup percentage. Retirement Account Growth Calculator Estimate future retirement-account value from a current balance, annual deposits, employer match, return, and years. 50-30-20 Budget Allocation Calculator Split a monthly income into needs, wants, and savings using the selected 50/30/20 planning convention. 70-20-10 Money Allocation Calculator Split income into living costs, saving or investing, and giving or flexible goals using a 70/20/10 convention. Hourly Pay to Annual Income Calculator Convert hourly pay, weekly hours, and working weeks into gross annual and monthly income equivalents. Annuity Future Value Calculator Estimate the future value of equal periodic deposits under a constant periodic interest rate. Annuity Payout Calculator Calculate the equal periodic payout from a present balance, interest rate, and payout term. Annuity Present Value Calculator Calculate the present value of equal future payments under a constant periodic discount rate. Annual Percentage Rate from Interest Cost Annualize an interest charge from principal and elapsed days using a simple non-compounded APR convention. Annual Percentage Yield Calculator Convert a nominal annual rate and compounding frequency into an effective annual yield. Accounts Receivable Days Calculator Estimate average collection days from receivables, credit sales, and the selected days-per-year convention. Adjustable-Rate Mortgage Payment Scenario Compare initial and reset payments for an adjustable-rate mortgage under two explicitly entered fixed rates. Vehicle Loan Payment Calculator Estimate a vehicle-loan payment from price, upfront contribution, fees, rate, and term. Average Variable Cost Calculator Calculate average variable cost from total variable cost and units produced. Balance Transfer Fee Calculator Estimate an upfront transfer fee and resulting balance from a card or loan balance and a stated fee percentage. Balloon Loan Balance Calculator Estimate the remaining balance after equal payments on a fixed-rate loan when the term is shorter than full amortization. Biweekly Mortgage Payment Calculator Estimate a fixed-rate mortgage payment every two weeks and compare its simple annual payment total. Bond Equivalent Yield Calculator Annualize a discount instrument's price gain using face value, purchase price, and days to maturity. Current Bond Yield Calculator Calculate a bond's simple current yield from annual coupon income and market price. Blended Interest Rate Calculator Calculate the weighted average rate across two balances using their amounts as weights. Compound Growth Calculator Project a starting value through repeated periods of constant percentage growth or decline. Personal Budget Balance Calculator Calculate monthly budget balance, planned savings, and remaining amount from income and spending categories. Build or Buy Cost Comparison Calculator Compare total build and purchase costs for a selected quantity using fixed and per-unit assumptions. Cash Burn Rate and Runway Calculator Calculate average monthly cash burn and estimated runway from starting cash, current cash, and elapsed months. Vehicle Payment Affordability Calculator Compare an estimated vehicle loan payment with a monthly payment budget after a down payment. Straight-Line Vehicle Depreciation Calculator Estimate annual straight-line depreciation and current value from purchase value, residual value, and age. Cash-Back Reward Calculator Calculate gross cash-back rewards and net reward after an annual fee from spending and a reward rate. Cash-on-Cash Return Calculator Calculate a simple cash-on-cash return from annual cash flow and the cash invested. Customer Churn Rate Calculator Calculate customer churn and retention percentages from customers at the start of a period and customers lost. Cost of Goods Sold Calculator Calculate cost of goods sold from beginning inventory, purchases, and ending inventory. Combined Ratio Calculator Calculate a descriptive combined claims-and-expense ratio against earned premium. Weighted Average Cost of Capital Calculator Calculate a weighted average cost of capital from equity and debt values and supplied financing costs. Total Cost of Doing Business Calculator Calculate total and average cost from fixed cost, variable cost per unit, and output volume. CAPM Cost of Equity Calculator Calculate a supplied beta-based cost of equity using the capital asset pricing model. Bond Coupon Payment Calculator Calculate annual and per-period coupon payments from face value, coupon rate, and payment frequency. Bond Coupon Rate Calculator Calculate a bond coupon rate from annual coupon cash flow and face value. Credit Utilization Ratio Calculator Calculate total revolving credit utilization from balances and available limits. Days Inventory Outstanding Calculator Calculate the average number of days inventory remains outstanding from average inventory and cost of goods sold. Days Payable Outstanding Calculator Calculate the average number of days a business takes to pay suppliers from average payables and purchases or COGS. Debt-to-Asset Ratio Calculator Calculate total debt as a percentage of total assets. Operating Expense Ratio Calculator Calculate operating expenses as a percentage of average assets or another supplied base. Shift Pay Scenario Calculator Calculate gross pay for regular and overtime hours using a supplied hourly rate and multiplier. Bond Price and Convexity Scenario Calculator Estimate a plain fixed-coupon bond price and cash-flow convexity from supplied terms and yield. Work Burndown Pace Calculator Calculate remaining work, planned daily pace, and the pace required to finish by a supplied deadline. Business Value Multiple Scenario Calculator Estimate a scenario value from revenue, growth, operating margin, and a supplied valuation multiple. Advertising CPC, CPM, and CTR Calculator Calculate cost per click, cost per thousand impressions, and click-through rate from campaign totals. Cross Exchange Rate Scenario Calculator Multiply two supplied currency quote ratios to derive a cross rate and convert an amount. Customer Effort Score Average Calculator Calculate the average of supplied customer-effort responses and the response count. Commercial Lease Occupancy Cost Calculator Estimate lease-period base rent, operating expenses, and combined occupancy cost from supplied area and rates. Comparative Advantage Opportunity-Cost Calculator Calculate opportunity costs for two producers and identify the lower-opportunity-cost producer for each good. Credit Spread Basis-Point Calculator Calculate the yield difference between a credit instrument and a benchmark in percentage points and basis points. Debt Service Coverage Ratio Calculator Calculate a coverage ratio from net operating income and annual debt service. Effective Duration Scenario Calculator Estimate effective duration from a base bond price, prices after a symmetric yield change, and the yield change size. Equivalent Compounding Rate Calculator Convert a nominal rate under one compounding frequency to an equivalent nominal rate under another frequency. Expected Utility Scenario Calculator Calculate expected value and variance for three outcomes with supplied probabilities and utility values. Full-Time Equivalent Calculator Convert total work hours into full-time equivalents using a supplied standard full-time schedule. Gross Rent Multiplier Calculator Calculate a property’s gross rent multiplier from price and annual gross rent. Income Gini Coefficient Calculator Calculate the Gini coefficient for a comma-separated list of nonnegative income or value observations. Economic Value Added Calculator Calculate economic value added from NOPAT, invested capital, and a supplied cost of capital. Free Cash Flow to Equity Calculator Estimate free cash flow to equity from net income, noncash expense, capital expenditure, working-capital change, and net borrowing. Cobb-Douglas Production Function Calculator Calculate output from total-factor productivity, capital, labor, and supplied production elasticities. Inflation-Adjusted Future Price Calculator Project a current price forward by a user-supplied annual inflation rate and number of years. Inflation-Adjusted Purchasing Power Calculator Estimate the present purchasing power of a future amount under a user-supplied inflation assumption. Time-Weighted Return Calculator Compound a sequence of period returns and calculate the cumulative and annualized result. Investment CAGR Calculator Calculate total return and compound annual growth rate from starting value, ending value, and holding years. Annualized Volatility Calculator Estimate annualized volatility from a list of periodic decimal returns. WACC Scenario Calculator Calculate WACC from market-value weights, required equity return, debt cost, and a visitor-supplied tax rate. After-Tax Return Scenario Calculator Apply a visitor-supplied tax rate to a pre-tax return and show the resulting tax drag. Break-Even Revenue Calculator Calculate revenue required to cover fixed costs when variable costs are entered as a share of revenue. Gross Profit from Margin Calculator Calculate gross profit and cost of goods sold from revenue and a user-supplied gross-margin rate. Operating Cost Share Calculator Calculate operating expenses as a share of revenue and show the amount remaining before other items. Rent-to-Income Ratio Calculator Calculate monthly rent as a share of monthly income and show income remaining before other costs. Housing Payment to Income Ratio Calculator Calculate a planned housing payment as a share of gross monthly income. Loan-to-Value Ratio Calculator Calculate loan-to-value percentage and property equity from a loan amount and property value. Dividend Yield Calculator Calculate annual dividend per share as a percentage of a share price. Earnings Yield Calculator Calculate earnings per share as a percentage of share price. Book Value per Share Calculator Calculate common-equity book value per share after subtracting preferred equity. Market Capitalization Calculator Calculate a company’s equity market capitalization from share price and shares outstanding. Enterprise Value Calculator Calculate a simple enterprise value from market capitalization, debt, and cash. Free Cash Flow Yield Calculator Calculate free cash flow as a percentage of market capitalization. Price-to-Earnings Ratio Calculator Calculate a share price multiple from share price and positive earnings per share. Black-Scholes Option Value Calculator Estimate a European call or put option value from price, strike, time, volatility, rates, and dividend yield. Bond Yield to Maturity Calculator Estimate the annual yield to maturity that equates a coupon bond's future cash flows with its current price. Vehicle Lease Payment Scenario Calculator Estimate a lease payment from capitalized cost, residual value, money factor, term, and a visitor-entered tax rate. Cash-Out Refinance Scenario Calculator Estimate a new mortgage payment and loan-to-value ratio when refinancing an existing balance and taking out cash. Credit Card Minimum Payment Scenario Calculator Estimate a credit-card minimum payment, monthly interest, principal reduction, and next balance from visitor-entered terms. Covered Interest Currency Forward Scenario Estimate a theoretical currency-forward rate from spot rate, two interest rates, and time to delivery. Debt Avalanche Payoff Planner Simulate three debts using minimum payments plus extra cash directed to the highest-rate balance first. Debt Consolidation Payment Scenario Compare three existing debt minimums with a new consolidated fixed-rate payment and total interest estimate. Debt Snowball Payoff Planner Simulate three debts using minimum payments plus extra cash directed to the smallest balance first. Deferred Annuity Present Value Calculator Estimate today's value of equal annuity payments that begin after a stated deferral period. Earned Value Management Calculator Calculate schedule and cost variances, performance indices, and a simple estimate at completion from project values. Forward Premium or Discount Calculator Calculate the annualized premium or discount implied by a forward price relative to a spot price. Implied Forward Interest Rate Calculator Calculate the annualized forward rate implied by two annual spot rates and two maturities. Futures Contract Profit and Margin Scenario Calculate a long or short futures position's price-change profit or loss and return on entered initial margin. GDP Gap Calculator Calculate the output gap between actual and potential gross domestic product. Minimum-Variance Hedge Ratio Calculator Estimate a hedge ratio from correlation, spot volatility, futures volatility, and exposure size. Herfindahl-Hirschman Market Concentration Calculator Calculate a partial-market HHI from entered percentage shares, including an explicit other-firms share. High-Low Cost Estimation Calculator Estimate variable cost per activity unit and fixed cost from high and low cost observations. Holding Period Return Calculator Calculate total holding-period return from beginning value, ending value, income, and fees. Constant-Product Impermanent Loss Calculator Estimate the relative value difference between a constant-product liquidity position and holding the two assets after a price-ratio change. Accumulated Depreciation Calculator Estimate straight-line depreciation accumulated over an elapsed portion of an asset's useful life and show its remaining book value. Actual Cash Value Scenario Calculator Estimate a simple actual-cash-value scenario by reducing a replacement cost by an entered depreciation percentage. AFFO Scenario Calculator Estimate adjusted funds from operations from FFO, entered non-cash adjustments, recurring capital spending, and straight-line rent adjustments. Customer Acquisition Cost Calculator Calculate customer acquisition cost from marketing spend, sales spend, and the number of newly acquired customers. Days Sales Outstanding Calculator Estimate how many days of credit sales are represented by average accounts receivable. Debt-to-Capital Ratio Calculator Calculate debt as a percentage of the entered debt-plus-equity capital structure. Debt-to-Equity Ratio Calculator Calculate the relationship between entered liabilities or debt and owners' equity. Defensive Interval Ratio Calculator Estimate how many days a business could cover entered daily cash operating expenses using liquid assets and receivables. Direct Material Price Variance Calculator Calculate the favorable or unfavorable price variance from actual and standard material prices and actual quantity. DuPont ROE Analysis Calculator Break return on equity into profit margin, asset turnover, and equity multiplier components. EBITDA Margin Calculator Calculate EBITDA as a percentage of revenue and show the entered operating cash-style amount before the excluded items. EV-to-EBITDA Multiple Calculator Calculate a simple enterprise-value multiple from entered enterprise value and EBITDA. Economic Profit Calculator Estimate economic profit by subtracting a capital charge from entered NOPAT. Fixed Asset Turnover Calculator Calculate net sales generated per unit of average net fixed assets. Gross Margin Return on Investment Calculator Estimate gross margin return on inventory investment from gross margin dollars and average inventory. Interest Coverage Ratio Calculator Calculate how many times entered EBIT covers an entered interest expense. Liquidity Coverage Ratio Scenario Calculator Calculate a simplified liquidity coverage ratio from high-quality liquid assets, gross outflows, and capped inflows. Loss Given Default Calculator Estimate loss given default and loss amount from exposure at default and an entered recovery-rate assumption. Levered Free Cash Flow Scenario Calculator Estimate cash flow available after operating needs, capital spending, working-capital changes, and net debt financing. Maximum Drawdown Scenario Calculator Calculate the percentage decline and recovery amount between an entered peak value and a later trough value. Quick Ratio (Acid-Test) Calculator Measure short-term liquidity using cash, short-term investments, and accounts receivable against current liabilities. Information Ratio Calculator Compare a portfolio's active return with its tracking error to estimate return per unit of active risk. Cross-Price Elasticity of Demand Calculator Estimate how the demand for one product changes when the price of another product changes, using the midpoint method. Basic Earnings per Share Calculator Calculate basic earnings per share from net income, preferred dividends, and weighted-average common shares. After-Repair Value Screening Calculator Estimate a transparent after-repair value range from three entered comparable sales and market-supported adjustments. Jensen's Alpha Calculator Compare an entered portfolio return with the return implied by a risk-free rate, market return, and portfolio beta. Treynor Ratio Calculator Calculate excess portfolio return per unit of systematic market risk using portfolio beta. Sortino Ratio Calculator Calculate a downside-risk-adjusted return from a comma-separated series of periodic returns and a target return. Weighted Portfolio Beta Calculator Estimate portfolio beta by weighting the entered individual holding betas, with automatic transparent normalization. Working Capital Turnover Ratio Calculator Calculate revenue generated per average working-capital unit from beginning and ending current-asset and current-liability balances. Occupancy Rate Calculator Calculate occupied and vacant shares from occupied units and the available-unit base for a property, facility, room set, or capacity plan. Net Effective Rent Calculator Spread free rent and one-time concessions across a lease term while keeping recurring fees visible in the comparison. Prorated Rent Calculator Calculate a partial-period rent charge from full-period rent, the selected day count, and the number of days charged. Income Elasticity of Demand Calculator Measure how quantity demanded changes relative to income using midpoint percentage changes between two observations. Lerner Index Calculator Calculate the price-cost markup as a share of price from an entered price and marginal cost. CAPM Expected Return Calculator Estimate an asset's required or expected return from a risk-free rate, beta, and market return using the capital asset pricing model. Sharpe Ratio Calculator Calculate a historical Sharpe ratio from periodic returns, a same-period risk-free rate, and population standard deviation of excess returns. Price Elasticity of Demand Calculator Measure the midpoint percentage response of quantity demanded to a price change between two observations. Gross Margin Calculator Calculate gross profit, gross margin, and markup on cost from revenue and cost of goods sold. Operating Margin Calculator Calculate operating income and operating margin after cost of goods sold and entered operating expenses. Return on Capital Employed Calculator Estimate ROCE from operating profit and the average of beginning and ending capital employed. Return on Invested Capital Calculator Calculate ROIC from EBIT, an entered tax assumption, and average beginning and ending invested capital. WACC Capital Cost Calculator Estimate WACC from debt and equity values, their costs, and an explicit user-entered tax assumption. Sustainable Growth Rate Calculator Estimate a stable-policy growth rate from return on equity and the share of earnings retained in the business. Total Asset Turnover Calculator Calculate net sales generated per average total-asset unit using beginning and ending asset balances. 28/36 Housing Affordability Guideline Calculator Compare a monthly housing cost and other debt with the 28% housing and 36% total-debt planning benchmarks. 3× Rent Income Screening Calculator Compare gross monthly income with a common three-times-rent screening benchmark and show the reverse rent share. Combined Loan-to-Value (CLTV) Calculator Calculate the combined loan-to-value ratio from property value and multiple debts secured by the property. Consumer Surplus Triangle Calculator Estimate consumer surplus from a maximum willingness to pay, market price, and purchased quantity under a straight-line demand model. Disposable Income After Deductions Calculator Subtract visitor-entered taxes and mandatory deductions from gross income for a clear disposable-income estimate. Discretionary Income After Essentials Calculator Estimate money left after entered taxes, mandatory deductions, and essential living expenses. Early Retirement Savings Target Calculator Build a transparent retirement scenario from a target age, spending gap, savings, return, and visitor-supplied withdrawal rate. Enterprise Value to Sales (EV/Sales) Calculator Calculate enterprise value and the EV-to-sales valuation multiple from market capitalization, debt, cash, and annual sales. Bradford Factor Absence Score Calculator Calculate a descriptive Bradford Factor score from absence instances and total absence days. Capital Gains Yield Calculator Estimate net capital gain or loss and its yield on an entered purchase price after transaction costs. Cost per Action (CPA) Calculator Calculate advertising cost per action and compare it with contribution per conversion and campaign results. EBIT Calculator Estimate earnings before interest and taxes by adding entered interest and income-tax adjustments back to net income. Earnings Before Tax (EBT) Calculator Calculate pre-tax earnings by adding income-tax expense or benefit back to net income. Effective Corporate Tax Rate Calculator Calculate an accounting effective tax rate from pre-tax income and entered income-tax expense or benefit. Consulting Project Fee Calculator Estimate a consulting project fee from billable hours, direct expenses, overhead, and a target profit margin. Dividend per Share Calculator Calculate dividend per share and annualized distributions from a payment amount, shares outstanding, and payment schedule. Cell Phone Plan Cost Comparison Calculator Compare two phone plans using recurring service, device, add-on, one-time fees, and a chosen comparison period. Trailing Twelve Months (TTM) Calculator Sum twelve consecutive monthly financial values and compare the latest six months with the preceding six months. Put–Call Parity Calculator Check the no-arbitrage relationship between European call and put premiums, the underlying price, strike, rates, dividends, and time to expiry. Pre-Money and Post-Money Valuation Calculator Calculate post-money valuation, investor ownership, and existing-owner dilution from a pre-money valuation and new investment. Lump Sum plus Monthly Investment Growth Calculator Project the future value of an initial lump sum combined with equal end-of-month contributions under a nominal annual return compounded monthly. FIFO Inventory Costing Calculator Calculate cost of goods sold and ending inventory value from inventory layers consumed in first-in, first-out order. Graham Number Screening Calculator Calculate the classic Graham-number screening value from positive earnings per share and book value per share. Currency Carry Trade Scenario Calculator Estimate the base-currency result of borrowing one currency, investing the converted amount at another rate, and applying a future exchange rate. HR Software ROI Calculator Estimate first-year return on investment and payback time from labor savings, software cost, and implementation cost. Gold Melt Value Calculator Estimate the melt value of gold from weight, purity, fine-gold price, and an optional buyer discount. Streaming Royalty Scenario Calculator Model an entered stream count and effective rate as a transparent scenario, then apply rights-holder share, distributor fees, and other deductions. Business Budget Balance Calculator Combine operating income streams, non-operating receipts, one-time setup costs, salaries, and recurring expenses into a transparent business-period budget. Deadweight Loss Triangle Calculator Estimate the triangular welfare loss from a price change and quantity change under a linear supply-and-demand approximation. Financial Leverage Ratio Calculator Calculate total assets, implied liabilities, the assets-to-equity leverage ratio, and the liabilities share from a simple balance-sheet snapshot. Free Cash Flow to Firm (FCFF) Calculator Estimate FCFF from net income, EBIT, EBITDA, or operating cash flow while keeping the tax shield and reinvestment inputs visible. Acquisition Goodwill Calculator Estimate goodwill or a bargain-purchase amount from purchase consideration and the fair values of identifiable assets and liabilities. Fixed Deposit Maturity Calculator Compare simple and cumulative fixed-deposit maturity, interest earned, effective yield, and average interest per period without assuming a country-specific bank rule. Price-to-Book Ratio Calculator Compare a share price with book value per share and show the implied market capitalization and book-equity scale. Price-to-Sales Ratio Calculator Calculate a price-to-sales multiple from share price, sales per share, and shares outstanding while keeping market value and sales scale visible. PEG Ratio Calculator Calculate a price-to-earnings multiple and divide it by an entered annual earnings-growth percentage to create a transparent PEG scenario. Unlevered Beta Calculator Remove an entered capital-structure effect from a levered beta using debt, equity, and an explicit tax-rate assumption. Net Debt Calculator Combine short-term debt, long-term debt, lease liabilities, cash, and short-term investments into a transparent net-debt scenario. Profitability Index Calculator Compare the present value of project benefits with present value of costs and report the profitability index and value surplus. Net Operating Income Calculator Estimate property net operating income from scheduled income, other operating income, vacancy loss, and operating expenses. Operating Cash Flow Ratio Calculator Compare operating cash flow with current liabilities and show the percentage coverage of the entered short-term obligation base. Net Operating Assets Calculator Calculate net operating assets from current and non-current operating assets and liabilities while keeping the operating boundary explicit. Real-Estate Commission Calculator Estimate a property-sale commission, an optional commission tax or VAT scenario, additional fees, and the seller proceeds before other closing items. Discounted Cash Flow (DCF) Scenario Estimate the present value of five forecast cash flows and a Gordon-growth terminal value, then compare the result with an initial investment. Finance Charge from a Payment Schedule Estimate the total scheduled finance charge from the amount financed, equal periodic payment, number of payments, and stated cash fees. Future Salary Growth Estimate Project an annual pay amount after repeated percentage increases or decreases, with a clear nominal-growth boundary. Pay Raise and New Pay Calculate the amount and new value of a one-time percentage pay raise for any stated pay period or currency unit. Price per Share and Enterprise-Value Bridge Translate equity value and basic or diluted shares into implied price per share, then show a simple debt-and-cash enterprise-value bridge. Stock Split and Reverse-Split Scenario Calculate post-split shares, price, dividend per share, and position value for a forward or reverse stock split ratio. Weighted Average Stock Cost Combine two share purchases and transaction fees to estimate total cost, average cost per share, current position value, and unrealized change. Investment Fee Drag Scenario Compare a fee-free compound-growth scenario with a simplified annual-fee scenario to show how recurring fees can reduce ending value. Sinking Fund Contribution Estimate the regular end-of-period contribution needed to reach a future target after accounting for an existing balance and periodic growth. Residual Income and Capital Charge Measure income left after applying a required return to an invested capital base, with the implied return and value spread shown together. Operating Asset Turnover Calculate revenue generated per unit of average operating assets and show the reciprocal asset intensity and days-equivalent view. Return on Ad Spend (ROAS) Compare attributed conversion value with advertising spend and optionally translate the result into gross-profit-after-ad-spend. LIFO Inventory Costing Calculator Use a periodic last-in, first-out layer worksheet to estimate ending inventory cost and cost of goods sold from beginning stock and two purchase layers. Insurance Loss Ratio Calculator Calculate incurred losses as a percentage of earned premium and show the same relationship as a ratio and simple premium-minus-loss amount. Vehicle Lease Mileage Overage Calculator Estimate contracted mileage, expected mileage, excess distance, and a possible end-of-lease mileage charge from the allowance and rate in a lease quote. Car Loan Refinance Comparison Calculator Compare the estimated payment and remaining repayment cost of a current vehicle loan with a new fixed-rate term that includes refinance fees. Modified Internal Rate of Return Calculator Estimate MIRR from a series of periodic cash flows by discounting negative flows at a finance rate and compounding positive flows at a reinvestment rate. Covered Interest Rate Parity Calculator Estimate a no-arbitrage forward exchange rate from a spot quote, domestic and foreign interest rates, term, and an observed forward scenario. Progressive Tax Bracket Calculator Estimate tax from three entered thresholds and four marginal rates, then show the effective rate, marginal rate, and income remaining. Gross-to-Net and Net-to-Gross Pay Calculator Convert a gross pay amount to net pay or solve for gross pay from a target net amount using entered percentage deductions and fixed deductions. Effective Annual Interest Rate Calculator Convert a nominal annual rate and compounding frequency into a periodic rate, effective annual rate, and compounding difference. Real Interest Rate Calculator Compare a nominal interest rate with an entered inflation rate using the exact Fisher relation and the simple nominal-minus-inflation approximation. Taxable-Equivalent Yield Calculator Convert a tax-exempt yield into the taxable yield that would leave the same after-tax return at an entered tax rate. GST and QST Calculator Estimate GST, QST, combined tax, and the after-tax amount with visitor-entered rates and a transparent choice of QST tax base. Mortgage Points Break-Even Calculator Estimate the upfront cost, monthly saving, and break-even time for mortgage points using the payment figures from a lender's offer. Mortgage Extra Payment and Interest-Saving Calculator Estimate how an extra monthly payment or one-time principal payment changes the payoff time and interest of a fixed amortizing loan. Safety Stock and Reorder Point Calculator Estimate demand variability during lead time, safety stock, and a variability-aware reorder point from demand and lead-time inputs. Lease Money Factor and APR Approximation Calculator Convert a vehicle lease money factor to an approximate annual percentage rate, or convert an entered rate back to a money factor for comparison. Website Advertising Revenue Calculator Estimate clicks, advertising revenue, revenue per thousand page views, and combined revenue from page views, click-through rate, and earnings per click. Mileage Reimbursement and Travel-Cost Calculator Estimate reimbursement, actual distance cost, and the difference between an entered travel rate and your own cost assumptions. Rental Property Cash-Flow and Yield Calculator Estimate effective rental income, operating cash flow, net operating income, cap rate, cash-on-cash return, and debt-service coverage from entered property assumptions. Mortgage Prepayment Penalty Scenario Calculator Compare common entered penalty methods—percentage of balance, months of interest, or fixed fee—with an optional contract cap. Earnest Money Deposit Calculator Calculate an earnest-money deposit from a purchase-price percentage or calculate its percentage from an entered deposit, then compare it with a planned down payment. Price per Square Meter Calculator Calculate property or land price per square meter and convert the result to price per square foot for international comparisons. Labor Productivity and Hours Calculator Calculate output per labor hour, total labor hours, and the hours required for a target output from entered workers, hours, and output assumptions. Forex Pip Value Calculator Calculate the value of one forex pip for a chosen lot size, contract unit, pip size, and account-currency conversion rate. Forex Pip Cost Calculator Estimate the account-currency cost of a chosen pip movement and compare one-way and simple round-trip scenarios. Forex Position Size Calculator Estimate a forex lot size from account equity, risk percentage, stop-loss distance, slippage allowance, and commission assumptions. Forex Margin and Leverage Calculator Estimate position notional, equivalent margin, margin rate, free equity, and margin usage from a forex position and leverage assumption. Forex Spread Cost Calculator Convert bid and ask prices into spread pips and estimate the account-currency cost of crossing that spread for a position. Trading Profit and Loss Calculator Estimate gross and net trading P&L for long or short positions using entry price, exit price, quantity, multiplier, conversion rate, and fees. Gold Weight and Melt Value Calculator Convert gold weight in grams, kilograms, or troy ounces into fine-gold content and an estimated metal value. Gold Futures Notional Value Calculator Estimate gold futures exposure, notional value, tick value, and an entered initial-margin scenario from price and contract size. Crude Oil Contract Notional Value Calculator Estimate crude-oil exposure, notional value, tick value, and an entered initial-margin scenario from price and barrels per contract. Trading Margin and Liquidation Scenario Calculator Estimate an illustrative maintenance threshold and liquidation price from entry, quantity, margin percentages, fees, equity, and direction. Buying Power and Margin Capacity Scenario Calculator Estimate margin excess and a transparent additional-notional scenario from equity, an existing position, reserve cash, and entered margin percentages. Call and Put Option Payoff Calculator Calculate a single call or put option's expiration payoff, premium effect, net result, and simple break-even for a long or short position. UK Capital Gains Tax Scenario Calculator Estimate UK-style capital gains tax by applying entered losses, annual exempt amount, unused basic-rate band, and two entered gain rates. US Child Tax Credit Scenario Calculator Estimate a US-style child tax credit scenario with entered child count, credit amount, income phaseout, tax liability, and refundable limits. Business Loan Payment and Cost Calculator Model a fixed-rate business loan with payment frequency, origination fee, and optional extra payment to see payoff time and total financing cost. GDP Deflator Calculator Calculate the implicit GDP deflator from nominal and real GDP while keeping the base-year index convention visible. Single-Sum Future Value Calculator Project one present amount forward with a stated annual rate, compounding frequency, and time period. Multi-Method Depreciation Calculator Compare straight-line, double-declining-balance, and sum-of-the-years-digits book depreciation for a depreciable asset. Credit Card Statement Interest Calculator Estimate one statement-period interest charge, fees, payment coverage, and remaining balance from a starting balance and APR. Free-Float Shares Calculator Estimate publicly available shares and the free-float percentage from shares outstanding and explicitly excluded holdings. Hourly Salary with Overtime Calculator Annualize regular and overtime hours into weekly, annual, monthly-average, and effective hourly gross pay without guessing local wage law. Interest-Only Mortgage Payment Screen Estimate the scheduled interest-only payment, interest paid during the interest-only period, and principal balance that remains when the period ends. EBITDA Reconciliation Calculator Reconcile EBITDA from net income, interest, income tax, depreciation, amortization, and revenue, then show the resulting margin. Liquid Net Worth Calculator Compare liquid assets with total liabilities, then contrast that liquidity view with total net worth after including illiquid assets. Deferred-Payment Loan Scenario Calculator Estimate the balance after a payment deferral and the later fixed payment under either capitalized interest or interest-paid-during-deferral assumptions. Debt-to-Income (DTI) Ratio Share of gross monthly income spent on debt payments, with a plain-English risk verdict. Net Worth Assets minus liabilities, with both sides of the balance shown. 50/30/20 Budget Split Split after-tax income into needs, wants, and savings at 50/30/20. Loan Comparison (A vs B) Monthly payments for two loan scenarios side by side. IRR Estimate Internal rate of return from a cash-flow series. Dividend Payout Ratio Calculator Calculate dividend payout and retention ratios from dividends and net income for one period. Down Payment Calculator Estimate down payment, closing costs, upfront cash, and amount financed from transparent percentages. Loan Interest Rate Calculator Solve a fixed loan's nominal and effective annual rate from principal, payment, and whole-month term. Credit Card Payoff Calculator Estimate payoff time and interest for a fixed monthly payment and APR. Required Minimum Distribution Estimate Estimate an original owner's IRA RMD using the IRS Uniform Lifetime Table for ages 73 and older. Certificate of Deposit Calculator Estimate CD maturity value and interest from principal, APY, term, and compounding frequency. House Affordability Calculator Estimate a planning price from income, debts, down payment, housing ratio, rate, and taxes or insurance. Payback Period Calculator Estimate simple and discounted payback from an initial investment and ordered annual cash flows. Rent Affordability Estimate Estimate a rent guideline from gross income, an entered target percentage, and monthly debt payments.

Adult BMI Screening Calculate body mass index from weight and height and view CDC screening categories for adults age 20 and older, without treating BMI as a diagnosis or a body-fat measurement. Adult Maintenance Energy Estimate Estimate daily maintenance energy expenditure using the sex-specific Mifflin-St Jeor resting-energy equation and a clearly labeled heuristic activity multiplier, without prescribing calorie intake. Adult BMI Reference Weight Interval Translate the CDC adult BMI reference interval into weights for your height, clearly distinguishing a screening reference from an individual ideal weight or treatment goal. Weight Change Arithmetic Timeline Compare two adult body weights and calculate the arithmetic duration at a user-assumed weekly change, without claiming that the pace, target, or timeline is safe or physiologically predictable. Fat-Free and Fat Mass Estimate Split adult body weight into estimated fat mass and fat-free mass using a supplied body-fat percentage, without mislabeling all fat-free tissue as muscle. Adult Resting Energy and BMR Proxy Estimate resting energy expenditure with the male or female Mifflin-St Jeor coefficient, while distinguishing this common BMR proxy from a measured basal metabolic rate. Adult Age-Predicted Heart Rate Estimate maximum heart rate with the Tanaka research equation and calculate a selected percentage of that estimate, without presenting a safe ceiling or exercise prescription. Tablet Dosage Count Number of tablets for an ordered dose from tablet strength. Weight-Based Dose Total dose from body weight and per-kilogram ordering. IV Drip Rate Gravity drip rate in drops per minute plus pump rate in mL per hour. Liquid Dosage Volume Millilitres to pour for an ordered dose from bottle strength. Gestational Age Tracker Weeks and days since the last period at any reference date. Body Surface Area Calculator Estimate body surface area with the Mosteller height-and-weight formula for a transparent size comparison. Waist-to-Height Ratio Calculator Calculate waist-to-height ratio using measurements entered in the same unit. Alcohol Amount and Standard-Unit Calculator Calculate pure alcohol mass and an explicit standard-unit count from beverage volume, alcohol percentage, density, and a user-defined unit size. Maximum Heart Rate Estimate Estimate a theoretical maximum heart rate using a selected age-based equation for fitness planning only. Heart Rate Training Zone Calculator Calculate a heart-rate reserve training zone from resting heart rate, age-based maximum estimate, and lower and upper intensity percentages. Visual Acuity Ratio Scenario Calculator Convert a supplied Snellen-style numerator and denominator into a decimal acuity ratio and logMAR value. Six-Minute Walk Distance and Pace Calculator Calculate pace and speed from a walking distance and timed test interval. Ninety-Minute Sleep Cycle Time Calculator Estimate total time represented by a selected number of sleep cycles using a supplied cycle length. A Body Shape Index Arithmetic Calculator Calculate the A Body Shape Index from supplied waist, height, and BMI values. Adjusted Weight Arithmetic Calculator Calculate an adjusted-weight scenario from actual weight, reference weight, and a supplied correction factor. Body Frame Ratio Calculator Calculate a height-to-wrist circumference ratio from supplied measurements. Estimated Total Body Water Calculator Estimate total body water with a selected adult Watson-equation coefficient set. Caffeine Remaining Amount Calculator Estimate remaining caffeine from an initial amount, half-life, and elapsed time using exponential decay arithmetic. Circadian Phase Shift Arithmetic Calculator Normalize a clock phase after a supplied time shift across a 24-hour cycle. Cholesterol Unit Conversion Calculator Convert a supplied cholesterol value between mg/dL and mmol/L using the conventional factor. Conception and Due-Date Date Arithmetic Calculator Estimate date offsets from a supplied last menstrual period date using adjustable planning intervals. Dog-Walking Energy Estimate Calculator Estimate activity energy from body mass, walking duration, and a supplied MET value. Eight-Item Sleepiness Score Sum Calculator Sum eight supplied 0-to-3 item responses and calculate the mean response. Dietary Fiber Target Arithmetic Calculator Calculate a proportional fiber target from daily calories and a supplied grams-per-1,000-calories factor. Fat-Free Mass Index Calculator Calculate fat-free mass index from fat-free mass and height, with an optional height-normalized value. Glycemic Load Scenario Calculator Calculate glycemic load from carbohydrate grams, glycemic index, and number of servings. Hand Sanitizer Volume Calculator Calculate total sanitizer volume and active-liquid volume from uses, amount per use, and active fraction. Net Carbohydrate Arithmetic Calculator Calculate net carbohydrates by subtracting supplied fiber and sugar-alcohol amounts from total carbohydrates. Smoking Pack-Years Arithmetic Calculator Calculate pack-years from cigarettes per day and years of smoking history. Sleep Debt Arithmetic Calculator Calculate accumulated difference between a supplied nightly sleep need and actual sleep over multiple nights. Oxygen Cylinder Duration Estimate Estimate available ambient-equivalent gas and duration from cylinder water capacity, gauge pressures, ambient pressure, and a stated flow rate. Ankle-Brachial Index Calculator Calculate an ankle-brachial index from ankle systolic pressure and the higher of two entered brachial pressures. Alveolar–Arterial Oxygen Gradient Calculator Estimate alveolar oxygen pressure with the simplified alveolar gas equation and subtract arterial oxygen pressure to calculate the A–a gradient. Anion Gap Calculator Calculate the potassium-excluded anion gap from serum sodium, chloride, and bicarbonate values. Albumin/Globulin Ratio Calculator Derive globulin from total protein and albumin, then calculate the albumin-to-globulin ratio and each component’s share. APRI Liver Fibrosis Index Calculator Calculate the AST-to-platelet ratio index from AST, the laboratory’s AST upper limit of normal, and platelet count. AST/ALT Ratio Calculator Calculate the arithmetic ratio of aspartate aminotransferase to alanine aminotransferase and show the supporting difference and shares. 4Ts Score Worksheet for HIT Pretest Probability Add the four 4Ts clinical components into a transparent 0–8 point worksheet for heparin-induced thrombocytopenia assessment. Aldrete Post-Anesthesia Recovery Score Worksheet Add five post-anesthesia recovery domains into a transparent 0–10 Aldrete score worksheet with the component points kept visible. Apnea–Hypopnea Index (AHI) Calculator Calculate an apnea–hypopnea index from scored apnea events, hypopnea events, and the stated sleep or recording duration. Aortic Valve Area by Continuity Equation Estimate effective aortic valve area from LVOT diameter, LVOT velocity-time integral, and aortic valve velocity-time integral. Cat Quality-of-Life HHHHHMM Worksheet Record seven subjective pet-wellbeing domains on a 1–10 scale and review the total, average, lowest domain, and good-day balance. Cerebral Perfusion Pressure Calculator Estimate mean arterial pressure and cerebral perfusion pressure from systolic pressure, diastolic pressure, and intracranial pressure while keeping the clinical limits visible. ECG Boxes to Seconds Calculator Convert counted small and large ECG paper boxes into seconds and milliseconds for a selected 25 or 50 mm/s paper speed. Fagerström Test for Nicotine Dependence Calculator Score the six-item Fagerström nicotine-dependence screening questionnaire with a visible item total and a clear boundary between screening and clinical care. Fatigue Severity Scale Calculator Calculate the nine-response Fatigue Severity Scale total and mean from responses entered on the official or authorized form, with a clear boundary between arithmetic and clinical interpretation. Absolute Neutrophil Count Without Bands Calculator Calculate an absolute neutrophil count from the white blood cell count and mature neutrophil percentage when bands are intentionally excluded from the entered differential. Alvarado Appendicitis Screening Score Calculator Add the eight scored Alvarado/MANTRELS findings and show the transparent ten-point total without turning a screening score into a diagnosis. Adjusted Age for a Premature Baby Calculator Estimate corrected age from chronological age and gestational age at birth using a 40-week reference, with a separate display for weeks born early. Urine Albumin-to-Creatinine Ratio Calculator Normalize urine albumin and creatinine units and calculate the spot urine albumin-to-creatinine ratio in mg albumin per gram creatinine. Full Bishop Score Calculator Add the five components of the traditional Bishop score—dilation, effacement, station, consistency, and position—for a documented cervical examination. Apgar Score Calculator Add the five documented Apgar components—appearance, pulse, grimace, activity, and respiration—with transparent 0–2 point arithmetic and clinical boundaries. Braden Scale Score Calculator Add the six Braden pressure-injury risk subscales, show each contribution, and keep the commonly cited 18-point context separate from local clinical policy. Body Surface Area (BSA) Estimator Estimate body surface area from height and weight using selectable Mosteller, DuBois, or Haycock equations and compare the outputs without hiding formula differences. Estimated Adult Blood Volume Calculator Estimate adult total blood volume from sex-specific Nadler equations using height and weight, with liters, milliliters, and mL/kg shown separately. Beighton Hypermobility Score Calculator Add the five Beighton examination maneuvers as a transparent nine-point score, showing paired joint contributions and keeping age-specific interpretation separate. Barthel Index Calculator Add ten activities of daily living in a common 0–100 Barthel Index format and show the functional contributions without treating dependency bands as universal rules. BASDAI Symptom Score Calculator Calculate the six-question BASDAI symptom score from 0–10 responses, showing the first-four sum and the morning-stiffness average separately. APACHE II Severity Score Calculator Calculate the APACHE II arithmetic from 12 acute-physiology components, age points, and chronic-health points, with oxygenation mode and creatinine weighting made explicit. Brief Interview for Mental Status (BIMS) Score Calculator Add the component points of the 15-point Brief Interview for Mental Status structure while keeping the screening result separate from diagnosis. Child–Pugh Liver Function Score Calculator Add the five Child–Turcotte–Pugh components—bilirubin, albumin, INR, ascites, and encephalopathy—with the class boundaries and subjective fields clearly separated. Ejection Fraction Calculator Calculate stroke volume and left-ventricular ejection fraction from end-diastolic and end-systolic volumes, with the result kept separate from an echocardiography diagnosis. Absolute Eosinophil Count Calculator Estimate absolute eosinophil count from the total white-cell count and eosinophil percentage, showing both laboratory units and a cautious reference context. Cardiac Index Calculator Estimate cardiac index from cardiac output and body surface area, or derive cardiac output from heart rate and stroke volume before indexing it. Bladder Volume Calculator Estimate bladder volume from three ultrasound dimensions using a selectable ellipsoid correction factor, with transparent units and limitations. Duke Activity Status Index (DASI) Calculator Add the twelve scored DASI activity components and estimate the associated MET value without reproducing the instrument’s question wording. EPDS Scored Total Calculator Add ten already-scored Edinburgh Postnatal Depression Scale item values while keeping safety follow-up separate from a screening total. Cockcroft–Gault Creatinine Clearance Calculator Estimate adult creatinine clearance with the Cockcroft–Gault equation while clearly separating it from eGFR and medication-dosing decisions. Centor and McIsaac Score Calculator Add the documented sore-throat findings and choose the classic Centor or age-adjusted McIsaac model for a transparent screening score. CHA₂DS₂-VASc Score Calculator Calculate the documented CHA₂DS₂-VASc stroke-risk score with visible age, prior-stroke, vascular-disease, and sex-category points. HAS-BLED Bleeding Risk Score Calculator Add the HAS-BLED bleeding-risk components with separate renal, liver, age, INR, medication, and alcohol inputs and a modifiable-risk reminder. HEART Score Calculator Combine already-scored history, ECG, age, risk-factor, and troponin components into a transparent HEART score for appropriate clinical review. CURB-65 Pneumonia Severity Score Calculator Calculate the five-point CURB-65 structure from confusion, urea, respiratory rate, blood pressure, and age while keeping disposition decisions with clinicians. Absolute Neutrophil Count (ANC) Calculator Calculate the absolute neutrophil count from the white-cell count, segmented neutrophils, and bands while keeping units and interpretation boundaries visible. Albumin-Adjusted Calcium (Payne Formula) Calculator Estimate albumin-adjusted total calcium with the classic Payne equation while showing why ionized calcium and local laboratory methods still matter. BUN-to-Creatinine Ratio Calculator Calculate the BUN-to-creatinine ratio in conventional or SI laboratory units and show the normalized values used in the comparison. Fick Cardiac Output Calculator Estimate cardiac output and cardiac index from oxygen consumption and arterial-venous oxygen content difference using the Fick principle. Bicarbonate Deficit Estimate Calculator Estimate a bicarbonate-equivalent amount from body weight, base deficit, distribution factor, and a selected correction fraction while keeping medication decisions out of the result. Dog Life-Expectancy Range Calculator Estimate a dog’s remaining years from an entered age and a user-supplied lifespan range without presenting a breed or health prognosis. Menstrual Product Cost Comparison Calculator Compare recurring disposable-product costs with the monthly equivalent of a reusable option using your own prices and care assumptions. Intake and Output Totals Shift intake, output, and net fluid balance from comma lists. Clinical Unit Conversions Bedside mass, temperature, and dose conversions within families. Reconstitution Mix Volume Draw-up volume for a reconstituted vial dose. Body Fat Estimate Estimate adult body-fat percentage from height and circumference measurements using the U.S. Navy equations. TDEE Calculator Estimate resting energy and total daily energy expenditure with Mifflin-St Jeor or Katch-McArdle assumptions. Macronutrient Planning Calculator Turn an adult energy estimate into transparent planning amounts for protein, fat, and carbohydrate. Pregnancy Weight Gain Reference Show singleton-pregnancy weight-gain ranges from pre-pregnancy BMI and gestational week. Child Height Prediction Estimate Estimate mid-parental height and an illustrative range from the parents' heights. One Rep Max Calculator Estimate one-repetition maximum from a submaximal lift using Epley, Brzycki, or Lombardi. eGFR Calculator Estimate adult eGFR with the 2021 CKD-EPI creatinine equation without a race coefficient. BAC Estimate Estimate blood alcohol concentration with a transparent Widmark-style planning equation. Calories Burned Estimate Estimate activity energy expenditure from body mass, duration, and a selected MET value.

Total-Period Return on Investment Measure an investment's total-period gain or loss relative to its full cost, with proceeds explicitly including recovered principal and no unsupported payback-year estimate. Whole-Unit Break-Even Point Calculate the whole units needed to cover fixed costs and the matching revenue, alongside the theoretical fractional-unit threshold and contribution per unit. Target Margin or Markup Pricing Set a selling price using either a profit-margin target or a markup-on-cost target, and see both percentages so their different denominators are never confused. Net Cash Burn and Runway Estimate how long available cash lasts after accounting for monthly cash receipts and expenses, and distinguish positive burn from cash flows that do not deplete the balance. Entered-Rate Tax Addition or Removal Add a user-entered percentage tax to a base amount or recover the pre-tax amount from an inclusive total, without assuming a location, current rate, or legal tax treatment. Single or Sequential Discounts Calculate the sale price, total savings, and effective percentage reduction for one discount or two discounts applied sequentially rather than added together. Profit Margin and Markup Analysis Measure profit or loss from matched revenue and costs, showing margin on revenue separately from markup on cost, including loss-making and zero-cost cases. Straight-Line Depreciation Spread an asset's depreciable cost evenly over its useful life. Economic Order Quantity (EOQ) Optimal order size balancing ordering and holding costs. Target-Profit Sales Units Units to sell to cover fixed costs plus a profit target. Liquidity Ratios (Current and Quick) Short-term financial health from current assets and liabilities. Double-Declining Depreciation Accelerated depreciation schedule floored at salvage value. Price Elasticity of Demand (Midpoint) Demand responsiveness free of start-point bias, with elastic/inelastic verdict. Freelance Hourly Rate from Salary Billable rate covering salary, costs, and non-billable time. Margin of Safety How far sales can fall before losses, in currency and percent. Inventory Turnover and Days How fast stock sells through, plus days of inventory on hand. Inventory Reorder Point Stock level triggering a new order from daily use and lead time. Sales Commission Paycheck Take-home from base salary plus commission on sales. GDP by Expenditure Gross domestic product from consumption, investment, government, and net exports. Unemployment Rate Share of the labor force without work from two headcounts. Money Multiplier Maximum deposit expansion from a reserve ratio. Break-Even Units Calculator Find the unit sales and revenue needed to cover fixed costs when price and variable cost are known. Average Fixed Cost Calculator Calculate fixed cost per unit from total fixed costs and output quantity. Defects per Million Opportunities Calculator Calculate defects per million opportunities from defects, units, and opportunities per unit. Billable Hours and Revenue Calculator Estimate billable hours and gross revenue from available work hours, a billable utilization rate, and an hourly rate. Required Billable Rate Calculator Calculate the hourly billable rate needed to cover a target income and overhead across planned billable hours. 3D Printer Buy-or-Outsource Calculator Compare a fixed printer purchase plus in-house unit cost with a per-unit outsourcing price and find a simple break-even quantity. Absence Percentage Calculator Calculate absent days, attended days, and absence percentage from scheduled and missed days. Average Daily Room Rate Calculator Calculate hospitality average daily rate and occupancy from room revenue, rooms sold, and available room-nights. Employee Attrition Rate Calculator Calculate attrition and retention percentages from departures and average headcount over a selected period. Website Bounce Rate Calculator Calculate bounce and engaged-session percentages from single-page sessions and total sessions. PERT Three-Point Schedule Estimate Combine optimistic, most-likely, and pessimistic task durations into a weighted expected time, spread, and variance for early project planning. Takt Time Calculate the production pace required to meet demand from effective available time and demand per period. CV Screening and Interview Time Calculator Estimate recruiting workload from applicant count, review time, shortlist rate, interview rounds, and available workday hours. Marginal Cost Calculator Calculate the average marginal cost over an output interval from two total-cost observations and two production quantities. Marginal Revenue Calculator Calculate the average marginal revenue over a quantity interval from two total-revenue observations. Hire an Expert vs Train a Fresher Calculator Compare entered hiring, compensation, training, ramp-up, and planning-horizon assumptions for an experienced hire versus a new starter. Production Cycle Time Calculator Estimate total elapsed production time, average minutes per unit, and hourly throughput from batch, run-time, changeover, transfer, and parallel-station assumptions. Customer Acquisition Cost (CAC) Average fully-loaded spend required to win one new customer. Sales Funnel Conversion Rates Signup, visitor-to-buyer, and signup-to-buyer rates from three funnel stages. Overtime Pay Weekly paycheck split into regular and overtime pay at an adjustable threshold and multiplier. Contribution Margin Contribution margin dollars and ratio from sales and variable costs. Receivables Turnover and DSO Collection turns per year and days sales outstanding from credit sales. Debt-to-Equity Ratio Creditor versus owner financing per unit of equity. DuPont ROE Return on equity from margin, asset turnover, and leverage. Cost of Goods Sold Build COGS from beginning inventory, purchases, and ending inventory. Consumer Surplus Triangle Consumer surplus as the triangle under linear demand. Per-Capita Value Average per-person share of any aggregate total. Simple Customer Lifetime Value Lifetime margin from yearly margin times relationship length. Market Share Firm's percentage of total market sales. Two-Stage Markup Chain Wholesale then retail price from cost plus two margins on selling price. Project Buffer Contingency hours and padded total from a base estimate. Volumetric Shipping Weight Billable dimensional weight from package size and carrier divisor. Predetermined Overhead Rate Overhead rate from estimated cost and base. Sales Quota Tracker Attainment percent and remaining amount to quota. Direct Cost Variances Splits a cost gap into price and efficiency variances with U/F verdicts. Total Revenue Test Compares total revenue before and after a price change. Real Value from GDP Deflator Deflates a nominal amount into base-year dollars. CPI Inflation Rate Computes inflation between two CPI readings. A/B Two-Proportion Z-Test Tests whether two conversion rates differ at 5% significance. Checkout Total with Tip Adds discount, tax, and tip in the right order for a final bill. Customer Lifetime Value with Retention Estimates undiscounted customer lifetime value from order value, purchase frequency, gross margin, and annual churn. Price Ceiling Shortage Sketch Checks whether an entered price ceiling binds and reports the quantity gap at the supplied demand and supply values. Accounting Equation Check Check whether entered assets, liabilities, and equity satisfy the fundamental accounting equation. Working Capital Calculator Calculate working capital as current assets minus current liabilities for one reporting date. Cash Reconciliation Calculator Reconcile beginning cash with operating, investing, and financing cash flows to estimate ending cash. Retained Earnings Calculator Calculate ending retained earnings from beginning retained earnings, net income, and dividends. Cash Ratio Calculator Calculate the cash ratio from cash, cash equivalents, and current liabilities. Equity Multiplier Calculator Calculate the equity multiplier by dividing total assets by total equity. Cash Conversion Cycle Calculator Calculate the cash conversion cycle from inventory, receivables, and payables day assumptions. Degree of Operating Leverage Calculator Calculate the static-period degree of operating leverage from contribution margin and operating income. Times Interest Earned Calculator Calculate times interest earned by dividing EBIT by interest expense for one period.

Percentage Calculator Find a percentage of a number, then see the original number with that amount added or subtracted. Percentage Change Calculator Measure the increase or decrease from a positive starting value and compare the absolute change. Fraction Calculator Add, subtract, multiply, or divide two signed fractions and obtain an exact reduced fraction. Quadratic Equation Calculator Solve ax^2 + bx + c = 0 for its real roots and inspect the discriminant. Pythagorean Theorem Calculator Find a missing right-triangle hypotenuse or leg, plus the completed triangle's area and perimeter. Circle Area and Circumference Calculator Calculate a circle's area, circumference, and diameter from its radius. Triangle Area from Three Sides Use Heron's formula to calculate triangle area, perimeter, and the altitude to the first side. Rectangle Area, Perimeter, and Diagonal Calculate floor or panel area, boundary length, and corner-to-corner distance from two sides. Scientific Expression Calculator Evaluate arithmetic expressions with parentheses, powers, square roots, trigonometry, and logarithms. Slope, Distance, and Midpoint Analyze two points: slope of the line, distance between them, and their midpoint. Linear Equation Solver (ax + b = 0) Solve a one-variable linear equation exactly. 2x2 Linear System Solver Solve two equations in two unknowns with Cramer's rule. Trapezoid Area Area of a trapezoid from its two parallel sides and height. Sphere Volume and Surface Area Volume and surface area of a sphere from its radius. Cylinder Volume and Surface Area Volume and total surface area of a right circular cylinder. Exponential Growth and Decay Project discrete or continuous exponential change over time. Arithmetic and Geometric Sequences nth term and partial sum of a sequence from its first term and difference or ratio. Logarithm Calculator Evaluate logarithms in any valid base. Cone Volume and Surface Area Volume and total surface of a right circular cone. Rectangular Box Volume and Diagonal Volume, surface area, and space diagonal of a rectangular box. Right-Triangle Trigonometry Solver Opposite and adjacent sides from hypotenuse and acute angle in degrees. Parabola Vertex and Axis Turning point, axis of symmetry, and opening direction of y = ax^2 + bx + c. 3x3 Linear System Solver Solve three equations in x, y, z with Cramer's rule. Parallelogram Area and Perimeter Area from base and vertical height plus perimeter from side length. GCF and LCM Calculator Find the greatest common factor and least common multiple of two to one hundred whole numbers using exact integer arithmetic. Quadratic Roots Calculator Solve a quadratic equation and show its discriminant and real or complex roots. 2D Distance and Midpoint Calculator Find the straight-line distance and midpoint between two points on a Cartesian plane. Heron’s Triangle Area Calculator Calculate a triangle’s area from its three side lengths and check the triangle inequality. Circle Measurements Calculator Calculate a circle’s diameter, circumference, and area from its radius. Cylinder Volume and Surface Calculator Calculate the volume, lateral area, and total surface area of a right circular cylinder. Percentage Increase Calculator Calculate the absolute and percentage increase from an original value to a new value. Percentage Decrease Calculator Calculate the absolute and percentage decrease from an original value to a lower new value. Percentage Difference Calculator Compare two values using their absolute difference and the average of their magnitudes. Percentage-Point Change Calculator Find the percentage-point change and relative percent change between two rates. Fraction to Percentage Calculator Convert a numerator and denominator into a decimal, percentage, and simplified ratio view. Prime Factorization Calculator Break a positive whole number into its prime factors using exact integer arithmetic. Perfect Number Checker Check whether a positive whole number equals the sum of its proper positive divisors. Circular Sector Calculator Calculate a circular sector’s arc length and area from radius and central angle. Cone Volume and Surface Calculator Calculate the slant height, volume, and closed surface area of a right circular cone. Circular Aperture Area Calculator Calculate the area of a circular opening from its diameter or radius-equivalent diameter input. Azimuth from East and North Components Calculate a compass-style azimuth from east and north coordinate components. Hemisphere Area and Volume Calculator Calculate curved area, total surface area, and volume for a hemisphere from its radius. Ceiling and Floor Function Calculator Calculate the ceiling, floor, and fractional part of a real number. Two-Point Center of Mass Calculator Calculate the one-dimensional center of mass for two point masses at entered coordinates. Quadrilateral Area from Diagonals Calculator Calculate the area of a convex quadrilateral from its two diagonals and the angle between them. Babylonian Base-60 Numeral Converter Convert a nonnegative decimal integer into grouped base-60 positional digits for a simple Babylonian-style notation. Arithmetic Sequence Term and Sum Calculator Calculate a selected term and the finite sum of an arithmetic sequence from its first term and common difference. Donut and Annulus Geometry Calculator Calculate annulus area and cylindrical donut volume from outer radius, inner radius, and height. AAA Triangle Similarity Calculator Scale a triangle with a supplied similarity factor and calculate the new sides and area ratio. Right Triangle Angle and Hypotenuse Calculator Calculate an acute angle and hypotenuse from the opposite and adjacent legs of a right triangle. AAS Triangle Solver Solve the remaining angle and two sides of a triangle from two angles and one opposite side. Clock Hand Angle Calculator Calculate the smaller angle between analog clock hands from an hour and minute value. Binary Division Calculator Divide two nonnegative binary integers with exact binary quotient, remainder, and decimal text output. Absolute and Percentage Change Calculator Calculate signed change and percentage change from an original value to a new value. SAS Triangle Area Calculator Calculate the area and opposite side of a triangle from two sides and their included angle. Binary Fraction Converter Convert a nonnegative binary number with an optional fractional part into its exact decimal value. Binary Multiplication Calculator Multiply two nonnegative binary integers and show the exact binary and decimal products. Box Method Polynomial Multiplication Expand two linear binomials by multiplying the four box terms and collecting like powers. Axis-Aligned Ellipse Center Calculator Find the center of an axis-aligned ellipse from the quadratic and linear coefficients in its equation. Central Angle from Arc Length Calculate a circle's central angle and sector area from radius and arc length. Triangle Classification by Sides and Angles Classify a valid triangle as equilateral, isosceles, or scalene and as acute, right, or obtuse. Least Common Denominator Calculator Find the least common denominator and scaling multipliers for two positive integer denominators. Complementary Angle Calculator Calculate the angle that completes a given angle to a 90-degree complementary pair. Conic Section Classifier Classify a nonrotated quadratic conic from the x-squared, xy, and y-squared coefficients. Exact Decimal to Fraction Calculator Convert a finite decimal text into a reduced fraction without binary floating-point rounding. Quadratic Discriminant Calculator Calculate the discriminant and classify the real-root count of a quadratic equation. Direct Variation Calculator Calculate the output of a direct-variation relationship from its constant and input value. Finite Harmonic Series Calculator Calculate the finite harmonic sum Hₙ = 1 + 1/2 + … + 1/n and a large-n logarithmic approximation. Guitar Fret Position Calculator Calculate distance from the nut and remaining string length for an equal-temperament fret. 2×2 Characteristic Polynomial Calculator Calculate trace, determinant, and characteristic roots for a two-by-two matrix. Collatz Sequence Explorer Generate a bounded Collatz sequence from a positive integer and report steps to one and the maximum visited value. Finite Sequence Convolution Calculator Calculate the linear convolution of two comma-separated finite numeric sequences. 2D Euclidean Distance Calculator Calculate the straight-line distance between two points in a Cartesian plane. Binomial Coefficient Calculator Calculate the exact number of ways to choose k items from n items without regard to order. Logarithm Change-of-Base Calculator Calculate a logarithm in any valid base using natural logarithms. Cartesian to Polar Coordinates Calculator Convert a two-dimensional Cartesian point into radius and angle in polar coordinates. Absolute-Value Linear Equation Calculator Solve an equation of the form absolute value of a times x plus b equals c. Antilogarithm Calculator Calculate a positive base raised to a selected exponent and show the corresponding logarithm inverse operation. Circular Arc Length Calculator Calculate a circular arc length and sector area from radius and central angle in degrees. Inverse Cosine Angle Calculator Calculate the principal inverse-cosine angle in radians and degrees for an input from negative one to one. Inverse Sine Angle Calculator Calculate the principal inverse-sine angle in radians and degrees for an input from negative one to one. Inverse Tangent Angle Calculator Calculate the principal inverse-tangent angle in radians and degrees for a finite ratio. Oblique Triangle Included-Angle Area Calculator Calculate the area of a triangle from two sides and their included angle. Sphere Surface Area and Volume Calculator Calculate the surface area and volume of a sphere from its radius. Coordinate Triangle Area Calculator Calculate the area of a triangle from the x and y coordinates of its three vertices. Average Rate of Change Calculator Calculate the average rate of change between two coordinate points. Coordinate Triangle Centroid Calculator Calculate the centroid coordinates of a triangle from its three vertices. Least Common Multiple Calculator Calculate the greatest common divisor and least common multiple of two positive whole numbers. Fraction Comparison Calculator Compare two signed fractions exactly using cross-products and show their decimal values. Completing the Square Calculator Convert a quadratic polynomial into vertex form and return its vertex from coefficients. Complex Number Operation Calculator Add, subtract, multiply, or divide two complex numbers in rectangular form. Coterminal Angle Calculator Calculate a normalized angle and a selected coterminal angle after an integer number of full turns. Cube Root Calculator Calculate the real cube root of a signed number. Rectangle Diagonal Calculator Calculate the diagonal, area, and perimeter of a rectangle from its side lengths. Geometric Sequence Term and Sum Calculator Calculate a selected term and finite sum of a geometric sequence from its first term and common ratio. Trapezoid Area Calculator Calculate the area of a trapezoid from its two parallel bases and perpendicular height. Polynomial Addition and Subtraction Calculator Add or subtract two polynomials entered as comma-separated coefficients in descending-power order. Two-by-Two Adjoint Matrix Calculator Calculate the adjoint matrix and determinant of a supplied two-by-two matrix. Associative Property Check Calculator Compare the two groupings of three numbers for addition or multiplication. Binary Integer Operation Calculator Apply AND, OR, XOR, or binary addition to two nonnegative binary integers. Two-by-Two Cholesky Decomposition Calculator Factor a symmetric positive-definite two-by-two matrix into a lower triangular matrix and its transpose. Two-by-Two Column Space Calculator Determine the rank, determinant, and a basis description for the column space of a two-by-two matrix. Two-by-Two Infinity-Norm Condition Number Calculator Estimate the infinity-norm condition number of an invertible two-by-two matrix. Three-Dimensional Cosine Similarity Calculator Calculate dot product, cosine similarity, and the angle between two three-dimensional vectors. Two-by-Two Cramer’s Rule Calculator Solve a two-equation linear system with Cramer’s rule and show its determinant condition. Cross-Sectional Area from Volume Calculator Calculate area from a solid’s volume and a perpendicular length, then show the reciprocal volume check. Digital Root Calculator Reduce an integer repeatedly by digit sums until one decimal digit remains. Error Function and Normal-CDF Calculator Approximate erf(x) and the corresponding standard-normal cumulative probability. Floor Division and Remainder Calculator Calculate mathematical floor division and the remainder for two integers, including negative operands. Quadratic Surface Gradient Calculator Calculate the gradient and magnitude for f(x,y)=x²+y² at a supplied point. Two-Dimensional Gram-Schmidt Calculator Orthogonalize two independent two-dimensional vectors and return an orthonormal basis. Two-by-Two Hadamard Product Calculator Multiply corresponding entries of two two-by-two matrices element by element. Square Pyramid Height from Volume Calculator Calculate the perpendicular height of a square pyramid from volume and base side length. Fundamental Counting Principle Calculator Multiply the number of choices at each independent stage of a finite selection process. Hyperbolic Cosine Calculator Evaluate the hyperbolic cosine of a supplied real number. Integer-Order Bessel J Function Calculator Approximate the first-kind Bessel function Jₙ(x) for a small nonnegative integer order. Absolute Value and Sign Calculator Calculate the absolute value, sign, and distance from zero for a real number. Complex Number Rectangular-Form Calculator Calculate rectangular real and imaginary components from a complex magnitude and argument. Bitwise Integer Operations Calculator Calculate bitwise AND, OR, XOR, and left/right shifts for bounded nonnegative integers. Trigonometric Cofunction Calculator Calculate sine and cosine values together with their complementary-angle identities. Rolling Coin Rotation Paradox Calculator Compare center travel and spin counts for a coin rolling around the outside or inside of a fixed circle. Complex Conjugate and Modulus Calculator Calculate the complex conjugate, modulus, and modulus squared of a+bi. Consecutive Integer Sum Calculator Calculate the first and last integer and total sum for a run of consecutive integers. Principal Complex Root Calculator Calculate the principal nth root of a complex number from polar magnitude and argument. Cycloid Arch Geometry Calculator Calculate ideal height, arch length, and area for one cycloid arch generated by a rolling circle. Cyclomatic Complexity Calculator Calculate graph-based cyclomatic complexity from edges, nodes, and connected components. Descartes Rule of Signs Calculator Count coefficient sign changes and report possible positive and negative real-root counts for a polynomial. Symmetric 2×2 Matrix Eigenvalue Calculator Calculate eigenvalues and principal-axis rotation for a real symmetric 2×2 matrix. Diamond Problem Factor Pair Calculator Find the two numbers with a selected sum and product, if the real factor-pair equation has solutions. Positive Divisors and Divisor-Sum Calculator List the positive divisors of a bounded positive integer and calculate their count and sum. Dividing Radicals Numeric Calculator Calculate a quotient of two positive square-root expressions and report its decimal value. Cube Volume Surface Area and Diagonal Calculator Calculate the volume, surface area, and space diagonal of a cube from its side length. Largest Axis-Aligned Cube in a Cylinder Calculator Calculate the largest axis-aligned cube side that fits within a cylinder from cylinder radius and height. Decimal Degrees to Degrees-Minutes-Seconds Calculator Convert a signed decimal degree angle into degrees, arcminutes, and arcseconds. Cotangent from Angle Calculator Calculate sine, cosine, and cotangent for an angle in degrees when cotangent is defined. Distributive Property Expansion Calculator Expand a numerical product across a sum or difference and verify the equivalent total. Point-Slope Line Calculator Build a linear equation and y-intercept from one point and a known slope. Line x-Intercept Calculator Find the x-intercept of a line from its slope and y-intercept. Parallel Line Through a Point Calculator Build the equation of a line parallel to a reference slope through a chosen point. Perpendicular Line Through a Point Calculator Build the equation of a line perpendicular to a nonhorizontal reference slope through a chosen point. Quadratic Function Value Calculator Evaluate a quadratic at a chosen x-value and report its discriminant. Polynomial Evaluation Calculator Evaluate a polynomial from a coefficient list using Horner’s method. Binomial Expansion Term Calculator Calculate one selected term of (a+b)^n using its binomial coefficient. Arithmetic Series Sum Calculator Calculate the final term and total of a finite arithmetic series. Finite Geometric Series Sum Calculator Calculate the final term and total of a finite geometric series. Infinite Geometric Series Limit Calculator Check convergence and calculate the sum of an infinite geometric series when the absolute ratio is below one. Modular Addition Calculator Add two integers and return the least nonnegative remainder under a chosen modulus. Modular Subtraction Calculator Subtract two integers and return the least nonnegative remainder under a chosen modulus. Modular Multiplication Calculator Multiply two integers and return the least nonnegative remainder under a chosen modulus. Modular Division Calculator Solve a modular division by finding the multiplicative inverse when it exists. Regular Polygon Exterior Angle Calculator Calculate each exterior angle and the total exterior turn of a regular polygon. Regular Polygon Area Calculator Calculate the apothem, perimeter, and area of a regular polygon from its side count and side length. Spherical Cap Volume Calculator Calculate the volume of a spherical cap from the sphere radius and cap height. Square Pyramid Slant Height Calculator Calculate the slant height and lateral area of a regular square pyramid. Rhombus Area from Diagonals Calculator Calculate the area and side length of a rhombus from its perpendicular diagonals. Kite Area from Diagonals Calculator Calculate the area of a kite from its perpendicular diagonal lengths. Euler Characteristic of a Convex Polyhedron Calculator Check Euler’s V − E + F relation for a convex polyhedron from its vertices, edges, and faces. Circumscribed Circle of a Regular Polygon Calculator Calculate the circumradius, diameter, and apothem of a regular polygon from its side length and side count. Egyptian Fraction Decomposition Calculator Decompose a positive rational number into a greedy sum of distinct unit fractions. Exponential Notation Calculator Evaluate a mantissa times a power of ten and return its normalized scientific-notation form. Gamma Function Calculator Evaluate the Gamma function Γ(x) and its natural logarithm for a positive real input. Golden Ratio Calculator Calculate the golden ratio and its complementary reciprocal relationships from a positive reference length. Golden Rectangle Calculator Calculate the long side, area, perimeter, and diagonal of a golden rectangle from its short side. Regular Hexagonal Pyramid Surface Area Calculator Calculate the base, lateral, and total surface area of a regular hexagonal pyramid from side length and slant height. Circle Involute Parametric Point Calculator Calculate a point on the involute of a circle from its base radius and unwinding angle. Irregular Polygon Area and Perimeter Calculator Calculate the area and boundary length of a simple irregular polygon from ordered Cartesian vertices. Lagrange Taylor Error Bound Calculator Estimate the Lagrange remainder bound for a Taylor polynomial from derivative bound, distance, and polynomial degree. Trapezoidal Prism Lateral Area Calculator Calculate the lateral area and total surface area of a right trapezoidal prism from its base sides and prism length. Ellipse Latus Rectum Calculator Calculate an ellipse’s semi-latus rectum and full latus-rectum length from semi-major axis and eccentricity. Complex Number to Polar Form Calculator Convert a complex number a + bi into magnitude, radians, degrees, and polar-form notation. Complex Number to Rectangular Form Calculator Convert a complex magnitude and angle into real and imaginary rectangular components. Euclidean Algorithm Trace Calculator Find the greatest common divisor of two whole numbers and show the successive division remainders. Inscribed Angle from Arc Calculator Calculate an inscribed angle from its intercepted arc and show the corresponding central angle. Circle Equation from Diameter Endpoints Calculator Build a circle’s center, radius, and Cartesian equation from the two endpoints of a diameter. Exact Trigonometric Value Calculator Return common exact sine, cosine, and tangent values for standard degree angles, with decimal checks. Conical Frustum Surface Area Calculator Calculate the lateral and total surface area of a right circular conical frustum from its radii and slant height. Circle Center from Three Points Calculator Find the circumcenter and radius of the unique circle through three non-collinear points. Right-Triangle Similarity Calculator Compare the corresponding legs of two right triangles and report their scale-ratio difference. Condense Logarithms Calculator Combine three same-base logarithm terms into one equivalent logarithm and evaluate both forms numerically. Cross-Multiplication Checker Compare two fractions by cross-multiplying their numerators and denominators. Rectangle Dimensions from Area and Perimeter Find the longer and shorter sides and diagonal of a rectangle from its area and perimeter. Double-Angle Identity Calculator Calculate sin(2θ), cos(2θ), and tan(2θ) from the sine and cosine of θ. Engineering Notation Calculator Express a number as a coefficient multiplied by a power of ten whose exponent is a multiple of three. Intersection of Two Lines Calculator Solve two lines in standard form and report their intersection or parallel status. Right Triangle Checker Check three side lengths against the Pythagorean relationship and triangle inequality. 2×2 LU Decomposition Calculator Decompose a 2×2 matrix into lower-unit and upper-triangular factors and verify their determinant. 2D Vector Independence Calculator Determine whether two two-dimensional vectors are linearly independent from their determinant. 2×2 Null Space Calculator Check a 2×2 matrix determinant and return a representative null vector when the matrix is singular. Expand Logarithms Calculator Expand a logarithm of powered factors into a weighted sum of same-base logarithms and evaluate both forms. Three-Side Triangle Area Calculator Find the area, perimeter, semiperimeter, and inradius of a triangle when all three side lengths are known. ASA Triangle Solver Solve an angle-side-angle triangle from two angles and the side opposite the first angle. Triangle Centroid Calculator Find the centroid of a triangle from the coordinates of its three vertices and report its area. Complex Number to Trigonometric Form Convert a complex number from rectangular real-plus-imaginary form into magnitude and angle form. Cone Surface Area Calculator Calculate the slant height, base area, lateral area, and total surface area of a right circular cone. Cone Volume Calculator Calculate the volume and base area of a right circular cone from its radius and vertical height. Coordinate Distance and Midpoint Calculator Find the horizontal change, vertical change, straight-line distance, and midpoint between two Cartesian points. Ellipse Perimeter and Area Calculator Estimate an ellipse’s perimeter with Ramanujan’s approximation and calculate its area and eccentricity. Equivalent Ratio Calculator Solve the missing denominator in a proportion of the form a:b = c:x and verify the resulting ratio. Greatest Common Divisor Calculator Find the greatest common divisor, least common multiple, and reduced positive ratio of two whole numbers. Right-Triangle Hypotenuse Calculator Calculate the hypotenuse, area, perimeter, and acute angle of a right triangle from its two legs. Isosceles Triangle Height Calculator Find the height, area, perimeter, and base angles of an isosceles triangle from its equal side and base. Parallelogram Area and Perimeter Calculator Calculate a parallelogram’s area from its base and perpendicular height, then report its perimeter from the side length. Regular Polygon Calculator Calculate the perimeter, apothem, interior angle, and area of a regular polygon from its side count and side length. Rhombus Area and Perimeter Calculator Calculate a rhombus’s area, side length, perimeter, and acute angle from its two diagonals. 2D Point Rotation Calculator Rotate a Cartesian point about the origin and report its new coordinates, radius, and direction. Trapezoid Midsegment Calculator Find the segment joining the midpoints of a trapezoid’s legs, along with its base average and area. Truncated Cone Volume Calculator Calculate the volume, slant height, lateral area, and total surface area of a right circular truncated cone. 2D Vector Resultant Calculator Add two two-dimensional vectors and calculate the resultant components, magnitude, dot product, and cross-product z component. Vector Direction and Unit Vector Calculator Find a vector’s magnitude, direction angle, and unit-vector components from its x and y components. Mayan Numeral Converter Convert a non-negative decimal integer into the place-value digits and readable dot-and-bar notation of the Maya vigesimal numeral system. Möbius Strip Geometry Calculator Estimate the exact-parametrization surface area and boundary length of a one-half-twist Möbius strip from its centerline radius and half-width. Sinusoidal Phase-Shift Calculator Analyze a transformed sine or cosine function to find amplitude, period, horizontal phase shift, midline, and the value at a chosen x-coordinate. Prisoner’s Dilemma Payoff Calculator Test a symmetric two-player payoff set for the strict Prisoner’s Dilemma ordering and identify dominant defection and the one-shot Nash outcome. M/M/1 Queueing Calculator Calculate utilization, idle probability, average queue lengths, and waiting times for a stable single-server M/M/1 queue. Rational Zeros Theorem Calculator List rational-root candidates for an integer polynomial and test them exactly to identify the rational zeros of a linear, quadratic, or cubic polynomial. Significant Figures Calculator Round a measured or calculated value to a chosen number of significant figures while keeping the scientific-notation result visible. Terminating Decimal Checker Reduce a fraction, factor its denominator, and determine whether its base-10 decimal expansion terminates and how many places it needs. Logic Truth Table Calculator Evaluate a selected two-input Boolean connective for a chosen row and display the complete truth table for AND, OR, XOR, NAND, NOR, XNOR, or implication. Two’s Complement Converter Encode a signed integer into a fixed-width two’s-complement bit pattern and decode the same pattern back to its signed and unsigned values. Adding and Subtracting Fractions Add or subtract two fractions with a least-common-denominator walkthrough, reduced exact answer, mixed-number form, and decimal check. Binary Subtraction Calculator Subtract signed binary numbers, inspect the decimal check, see aligned operands, and encode the result in a chosen two’s-complement width when it fits. Crescent and Circle-Overlap Area Calculator Calculate the overlap and the two lune-shaped remainder areas formed by two intersecting circles, and identify which lune is a crescent. Interior and Exterior Triangle Angles Enter two interior angles of a triangle to find the missing interior angle, the three adjacent exterior angles, and both angle-sum checks. Cubic Equation Solver Solve a real cubic equation for all three roots, including repeated and complex-conjugate roots, and classify the root pattern with the cubic discriminant. 2×2 Eigenvalue and Eigenvector Calculator Find the trace, determinant, eigenvalues, and representative eigenvectors of a general real two-by-two matrix, including complex eigenvalues. Doubling Time Calculator Find how long a quantity takes to double under a constant percentage growth rate, or find the periodic rate needed to double in a chosen time. Average Percentage Calculator Find both the ordinary mean and the sample-size-weighted mean of a list of percentages so grouped survey or test results are not averaged incorrectly. Fractional Exponent Calculator Evaluate a base raised to a rational exponent, reduce the exponent fraction, show the equivalent root-power form, and reject non-real branches clearly. Compatible Numbers Estimator Round numbers to an easy place value for quick mental arithmetic, then compare the compatible-number estimate with the exact operation and its error. Gauss-Jordan Linear System Solver Solve a small square system of linear equations from a coefficient matrix and right-hand-side vector using reduced row echelon elimination. Linear Feedback Shift Register Sequence Step a binary Fibonacci-style LFSR with an explicit seed, tap list, and number of transitions. Odd-Order Magic Square Generator Generate the classic odd-order normal magic square and verify its common row, column, and diagonal sum. Negative Modulo Convention Calculator Compare Euclidean and truncating division results for negative dividends so the remainder convention is visible instead of assumed. Base-2 Logarithm Calculator Find the binary logarithm of a positive number and show the equivalent natural and common logarithms. Triangle Midsegment Calculator Find the segment joining the midpoints of two triangle sides and verify its parallel-side and scale relationships. Rectangle Dimensions from Perimeter Recover rectangle length and width from a known perimeter and a chosen length-to-width ratio. Hyperbolic Function Calculator Evaluate sinh, cosh, tanh, and the reciprocal hyperbolic functions for a real input. Long Addition with Carry Steps Add two nonnegative whole numbers and show the aligned decimal result and carry count using exact integer arithmetic. Long Multiplication with Partial Products Multiply two nonnegative whole numbers exactly and display the shifted partial products used by the column method. Divide Powers with the Same Base Simplify and evaluate a quotient of two powers that share the same nonzero base. Expanded Form of a Whole Number Rewrite a signed whole number as the sum of its nonzero place-value terms and find its digit sum. Test Associativity in Modular Arithmetic Compare both groupings of addition and multiplication after reducing integers modulo a positive modulus. Find the Missing Endpoint from a Midpoint Find the second endpoint of a line segment when one endpoint and the midpoint are known, with length and slope checks. Long Subtraction with Borrowing Subtract two nonnegative whole numbers exactly, show the signed difference, and count the borrowing steps. Rational or Irrational Number Classify a fraction or a principal square root as rational or irrational and show the reduced form. Relatively Prime Numbers Find the greatest common divisor, least common multiple, and Bézout coefficients to test whether two integers are coprime. Reference Angle Normalize an angle, identify its quadrant or axis, and calculate the reference angle with sine, cosine, and tangent checks. Power Set of a Finite Set List every subset of a small finite set and calculate the power-set cardinality 2ⁿ. Powers of i Reduce an integer power of the imaginary unit i using its four-step cycle and return its real and imaginary parts. Direct and Power Variation Constant Find the constant of proportionality and predict a target value for a direct or power-variation relationship. Area of a Circle Calculator Find the area, diameter, and circumference of a circle from its radius. Circumference Calculator Calculate a circle's circumference, radius, and area from its diameter. Cube Volume and Surface Area Calculator Calculate the volume, surface area, face area, and total edge length of a cube. Regular Pentagon Calculator Calculate the perimeter, apothem, circumradius, area, and interior angle of a regular pentagon from its side length. Regular Hexagon Calculator Calculate the perimeter, apothem, circumradius, area, and interior angle of a regular hexagon from its side length. Regular Octagon Calculator Calculate the perimeter, apothem, circumradius, area, and interior angle of a regular octagon from its side length. 30-60-90 Triangle Calculator Find every side, area, perimeter, and trigonometric ratio of a 30-60-90 right triangle from any one known side. Order of Magnitude Calculator Express a nonzero value in scientific notation and identify the nearest power of ten that describes its scale. Greater Than or Less Than Calculator Compare two numbers and show their exact ordering, signed difference, absolute difference, minimum, and maximum. Quaternion Arithmetic and Rotation Calculator Multiply two quaternions, inspect norms, conjugates, inverses, and rotate a 3D vector with a normalized quaternion. Subset and Set Difference Calculator Check whether one finite set is a subset or proper subset of another and list the elements missing from either direction. Union, Intersection, and Symmetric Difference Calculator Calculate the union, intersection, directional differences, symmetric difference, and cardinality relationship of two finite sets. 2×2 Singular Value Decomposition Calculator Compute the singular values, orthonormal U and Vᵀ factors, rank, condition number, and reconstruction error of a real 2×2 matrix. Pascal's Triangle Entry Calculator Find an exact binomial coefficient in Pascal's triangle and the sum of the selected row. Generalized Harmonic Number Calculator Calculate a finite generalized harmonic sum and show the last-term and average-term contributions. Two-Factor Partial Fraction Decomposition Calculator Decompose a rational expression with two distinct linear denominator factors and verify its value at a chosen x. 2D Vector Linear Combination Calculator Solve for the two coefficients that express a target 2D vector as a linear combination of two supplied vectors. Square Pyramid Block Count Calculator Count the unit blocks in a stepped square pyramid whose layers have side lengths from one block through the entered base side. Interval Notation Converter Build an interval and its matching inequality from finite or unbounded endpoints, endpoint inclusion, and an open or closed boundary choice. FOIL Binomial Expansion Calculator Expand two linear binomials, return the normalized quadratic coefficients, discriminant, and real or complex roots when the product is treated as an equation equal to zero. Negative Exponent Calculator Evaluate a nonzero base raised to a negative whole-number exponent and show the reciprocal relationship step by step. 2×2 Moore–Penrose Pseudoinverse Calculator Calculate a transparent Moore–Penrose pseudoinverse for a real 2×2 matrix, including full-rank, rank-one, and zero-matrix cases. Rise Over Run Slope Calculator Calculate rise, run, slope, direction angle, and y-intercept from two Cartesian points, while identifying a vertical line safely. Nearest Integer Rounding Calculator Round a real number to an integer using either half-away-from-zero or half-to-even tie handling, with the rounding distance shown. Two-Circle Triangulation Calculator Find the two possible planar intersection points from a baseline and two distances, exposing mirror-image ambiguity and the tangent case. Triangle Angle-Type Classifier Classify a triangle from its three side lengths and calculate its largest angle, perimeter, and semiperimeter. Oblique Triangle Area Calculator Calculate the area, third side, and altitude of an oblique triangle from two sides and their included obtuse angle. Triangle Base from Area and Height Solve for a triangle's base when its area and perpendicular height are known, then verify the area relationship. Triangle Interior and Exterior Angles Complete a triangle from two interior angles and calculate the adjacent exterior angles and their total. Coordinate Midpoint and Segment Calculator Find the midpoint, coordinate changes, and straight-line length between two points in a Cartesian plane. Heron's Formula Triangle Area Calculate a triangle's area, semiperimeter, perimeter, and inradius from its three side lengths. Equilateral Triangle Geometry Calculator Calculate the area, perimeter, height, inradius, and circumradius of an equilateral triangle from its side length. Regular Decagon Area and Geometry Calculate the area, perimeter, apothem, circumradius, and interior angle of a regular decagon from its side length. Regular Dodecagon Area and Geometry Calculate the area, perimeter, apothem, circumradius, and interior angle of a regular dodecagon from its side length. Regular Heptagon Area and Geometry Calculate the area, perimeter, apothem, circumradius, and interior angle of a regular heptagon from its side length. Regular Hexagonal Pyramid Volume Calculator Calculate the base area, volume, perimeter, apothem, and slant height of a regular hexagonal pyramid from its side and vertical height. Triangle Proportionality Theorem Calculator Solve a missing side segment when a line parallel to a triangle base creates two proportional smaller sides. Triangle Congruence by Side Lengths Compare two triangles by their three side lengths, test SSS congruence, and compare perimeter and area. Triangle Scale Factor and Area Change Calculate a triangle's linear scale factor and project how its perimeter and area change under a similar enlargement or reduction. 2×2 QR Decomposition Calculator Factor a nonsingular real 2×2 matrix into an orthogonal Q matrix and an upper-triangular R matrix, then check reconstruction and orthogonality errors. 2×2 Polar Decomposition Calculator Decompose an invertible real 2×2 matrix into an orthogonal factor Q and a symmetric positive-definite stretch factor H, with error checks for A = QH. 2D Vector Tensor Product Calculator Calculate the outer tensor product of two real two-dimensional vectors and report its four components, Frobenius norm, and rank-one consistency check. 3×4 Reduced Row-Echelon Form Calculator Transform a real 3×4 matrix into reduced row-echelon form with partial pivoting, then report rank and pivot columns without interpreting the matrix as a system solution. Cubic by Quadratic Polynomial Division Calculator Divide a cubic polynomial by a quadratic polynomial and return the linear quotient, linear remainder, and an identity check. Polynomial Graphing Sample Calculator Evaluate a polynomial across an evenly spaced interval and return a compact table for sketching its graph. Rectangle Diagonal and Angle Calculator Calculate a rectangle’s diagonal, diagonal angle, area, and perimeter from its length and width. Trapezoidal Prism Volume Calculator Calculate the volume of a right trapezoidal prism from its two parallel bases, trapezoid height, and prism length. Surface Area to Volume Ratio Calculator Calculate surface area, volume, and their ratio for a cube, sphere, or right circular cylinder. Galileo’s Paradox Finite Demonstration Count positive integers and perfect squares up to a finite limit to demonstrate the pairing behind Galileo’s infinity paradox without pretending to measure infinity. Hilbert’s Hotel Mapping Calculator Explore finite guest shifts and the classic countably infinite room mappings used to explain Hilbert’s hotel thought experiment. Multiplying Polynomials Calculator Multiply two polynomials from coefficient lists, combine like powers, and inspect every resulting coefficient. Elimination Method Calculator Solve a two-equation linear system by scaling and adding equations to eliminate the y variable, with the arithmetic shown. Substitution Method Calculator Solve a two-equation linear system by isolating y in the first equation, substituting into the second, and checking the ordered pair. One-Dimensional Inequality Graphing Calculator Solve a linear inequality, write its interval, and sample a visible x-window to make the open or closed endpoint and direction easy to check. Fundamental Trigonometric Identities Checker Check a supplied sine and cosine pair against the Pythagorean identity and calculate tangent and reciprocal identities when defined. Rationalize Denominator Calculator Remove one square-root term from a numeric denominator by multiplying by its conjugate, then show the equivalent radical form and a numeric check. Segment Addition Postulate Calculator Find a whole segment or a missing adjacent part from two segment lengths, with a closure check that makes the relationship visible. Triangle Inequality Calculator Check whether three positive lengths can form a non-degenerate triangle, show every inequality slack, and calculate Heron area when valid. Floor and Ceiling Function Calculator Compare floor, ceiling, truncation, fractional part, and an explicit nearest-integer rule for a real number, including negative values. Polish Notation and RPN Calculator Convert a bounded arithmetic expression from infix form to prefix Polish notation and postfix reverse Polish notation, then evaluate it without executing arbitrary code. Derivative at a Point (Central Difference) Estimates f'(a) from two nearby function values using the symmetric central-difference quotient. Simpson's 1/3 Rule Integral Approximates a definite integral from endpoint and midpoint values with one Simpson panel. Tangent Line Equation Builds the tangent line at x = a from the function value and derivative. Linear Inequality Solver Solves ax + b against zero and reports the ray solution with its boundary point. Quadratic Factoring Helper Reports the discriminant, root nature, and real roots of ax^2 + bx + c. Complex Number Arithmetic Adds, subtracts, multiplies, or divides two complex numbers and reports the magnitude. Variation Solver Evaluates direct, inverse, and joint variation models from the constant k. Absolute Value Equation Solver Solves |ax + b| = c by splitting into the positive and negative cases. Triangle Angles from Three Sides (Law of Cosines) All three interior angles of a triangle from its side lengths a, b, c. Circular Arc Length and Sector Area Arc length and sector area from a radius and central angle in degrees or radians. Ellipse Area Area enclosed by an ellipse from its semi-major and semi-minor axes. Completing the Square Vertex form a(x-h)^2+k and vertex (h, k) for a quadratic. Cubic Critical Points Stationary x-values where the derivative of a cubic is zero. Riemann Sums Left, right, and trapezoidal sums from evenly spaced heights. Polar Coordinate Converter Convert polar (r, degrees) to rectangular (x, y) and back. Average Rate of Change Secant slope (f(b)-f(a))/(b-a) between two points. Regular Polygon Area Area of a regular n-gon from side count and side length. Map Scale Distance Ground distance in cm, m, and km from a map length and 1:N scale. Synthetic Division Divide a polynomial by (x - c) in one row: quotient plus remainder. Ratio Test for Series Judge absolute convergence from consecutive-term ratios. Unit Circle Values Exact-feel sin, cos, tan for common angles via trig. Law of Sines (ASA Triangle) Solve a triangle from two angles and the side opposite A. Area Between Two Curves (Simpson) Approximates area between sampled top and bottom curves with one Simpson panel. Midpoint Riemann Sum Estimates a definite integral from function values sampled at the midpoint of each equal subinterval. Hemisphere Geometry Calculate a hemisphere's volume, curved surface area, and total surface area from its radius. Ellipsoid Volume Calculate the volume of an ellipsoid from its three semi-axis lengths. Pyramid Volume Calculate the volume of a pyramid from its base area and perpendicular height. Conical Frustum Volume Calculate the volume of a right circular frustum from its two radii and perpendicular height. Semicircle Geometry Calculate the area, curved arc length, and full perimeter of a semicircle from its radius. Kite Area Calculate the area of a kite from the lengths of its perpendicular diagonals. Coordinate Triangle Area Calculate a triangle's area and orientation from the Cartesian coordinates of its three vertices. SAS Triangle Area Calculate a triangle's area from two sides and their included angle. Triangle Centroid Find the centroid of a triangle from the Cartesian coordinates of its three vertices. 3D Vector Cross Product Calculate the cross product and magnitude of two three-dimensional Cartesian vectors. Fibonacci Number Calculate an exact Fibonacci number using F0=0, F1=1, and integer recurrence. Volume of a Parallelepiped Calculate the volume of a parallelepiped from three edge vectors. Divisibility Test Test whether one whole number divides another without a remainder. Factorial Calculate an exact nonnegative-integer factorial. Perfect Square Test Check whether a nonnegative whole number is the square of an integer. Perfect Cube Test Check whether a signed whole number is the cube of an integer. Prime Number Test Test whether a whole number is prime and report its smallest factor. Pythagorean Triples List integer right-triangle side triples up to a selected hypotenuse limit. Triangular Numbers Calculate the exact nth triangular number from a nonnegative index. Chinese Remainder Theorem Solve two simultaneous congruences with coprime positive moduli. Modular Multiplicative Inverse Find the integer that multiplies a value to 1 modulo a coprime modulus. Modular Exponentiation Calculate a nonnegative integer power modulo a positive modulus. Fermat's Little Theorem Check Check the modular result described by Fermat's little theorem for a prime modulus. Sum of Digits Add the decimal digits of a signed whole number without losing large integer digits. 3D Dot Product Calculate the scalar dot product of two three-dimensional Cartesian vectors from their six ordered components. Angle Between Two 3D Vectors Find the principal angle in degrees between two nonzero three-dimensional Cartesian vectors. 3D Vector Addition Add two three-dimensional Cartesian vectors component by component and return the summed x, y, and z values. 3D Vector Magnitude Calculate the Euclidean L2 magnitude of a three-dimensional vector from its x, y, and z components. 3D Unit Vector Normalize a nonzero three-dimensional Cartesian vector to a vector of Euclidean length one. Projection of One 3D Vector onto Another Calculate the vector projection of A onto nonzero vector B from their ordered three-dimensional components. Linear Interpolation Estimate y at an in-range x between two ordered points using a straight-line interpolation fraction. Bilinear Interpolation Interpolate a value inside an ordered rectangle from four finite corner values and an in-range x-y target. Equation of a Plane from a Normal and Point Build the Cartesian equation of a plane from a nonzero normal vector and one point on the plane. Distance from a Point to a Plane Calculate the unsigned and signed Cartesian distance from a point to a plane given by ax + by + cz + d = 0. Circumcenter of a 2D Triangle Find the Cartesian circumcenter and circumradius of a non-collinear triangle from its three ordered vertices. Orthocenter of a 2D Triangle Find the Cartesian orthocenter of a non-collinear triangle from its three ordered vertices. 3D Euclidean Distance Calculate the straight-line Euclidean distance between two ordered points in a three-dimensional Cartesian coordinate system. 3D Manhattan Distance Calculate the axis-aligned Manhattan distance between two ordered points in a three-dimensional Cartesian coordinate system. Circle Chord Length Find the straight chord length determined by a circle radius and a minor central angle measured in degrees. Great-Circle Distance Calculate the shortest spherical-surface distance and central angle between two latitude-longitude points on a sphere. Cartesian to Spherical Coordinates Convert one non-origin Cartesian point into radial distance, azimuth, and polar angle with degree outputs. Catenary Curve Height Evaluate the height of the canonical symmetric catenary y = a cosh(x/a) at a selected horizontal coordinate. Ring Torus Volume Calculate the volume of a non-self-intersecting ring torus from its major radius and smaller tube radius. Convex Trapezoid Perimeter Add the two parallel bases and two legs of a nondegenerate convex trapezoid after checking that the four lengths can form the shape. Regular Polygon Interior Angle Calculate one interior angle of a regular polygon from its whole-number count of sides. Minor Circular Segment Area Calculate the area between a circle chord and its minor arc from radius and included central angle. Absolute-Value Inequalities Solve |a*x+b| in relation to a nonnegative threshold and report the interval or solution meaning explicitly. Line Equation From Two Points Construct a normalized A*x+B*y+C=0 line from two distinct two-dimensional Cartesian points, including vertical lines. Circle Equation Build the standard circle equation from a center and positive radius, then return the expanded quadratic coefficients. 3x3 Matrix Determinant Calculate the determinant of a bounded finite numeric 3x3 matrix in row-major order. Ellipse Standard Form Construct the standard axis-aligned ellipse equation from a center and positive horizontal and vertical semiaxes. Foci of an Ellipse Find the focal distance, horizontal foci, and eccentricity from an ellipse center, semimajor axis, and semiminor axis. Ellipse Circumference Approximation Estimate the circumference of an ellipse with the clearly labeled Ramanujan II approximation and its shape parameter. Cylindrical Coordinates Convert Cartesian x, y, z coordinates to cylindrical rho, normalized azimuth, and unchanged z. Line of Intersection of Two Planes Find one finite point and a direction vector for the intersection line of two nonparallel planes. Hollow Cylinder Volume Calculate the material volume of a uniform hollow cylinder from outer radius, inner radius, and height. Torus Surface Area Calculate the surface area of an ordinary ring torus from its major and minor radii. Trapezoid Height Find the perpendicular height implied by two parallel bases and a positive trapezoid area. Regular Polygon Perimeter Calculate the perimeter of a regular polygon from an integral side count and common side length. Surface Area of a Triangular Prism Calculate the total surface area of a straight triangular prism from three valid base sides and prism length. Regular Tetrahedron Volume Calculate the volume of a regular tetrahedron from its common edge length. Matrix Addition Add two finite row-major 3x3 matrices entry by entry and return their deterministic matrix sum. Matrix by Scalar Multiply every entry of one finite row-major 3x3 matrix by one bounded scalar. Matrix Multiplication Multiply two finite row-major 3x3 matrices using ordered row-column dot products. Matrix Transpose Transpose a finite row-major 3x3 matrix by exchanging its row and column indices. Matrix Trace Sum the three main-diagonal entries of a finite row-major 3x3 matrix. Matrix Norm Calculate the Frobenius norm of a finite row-major 3x3 matrix from all nine squared entries. Matrix Power Raise a finite row-major 3x3 matrix to a bounded whole-number exponent from 0 through 12. Matrix Rank Estimate the numerical rank of a finite row-major 3x3 matrix with a documented scale-relative pivot tolerance. Cofactor Matrix Construct the signed 3x3 cofactor matrix of a finite row-major matrix from its nine 2x2 minors. Matrix Inverse Calculate the inverse of a finite row-major 3x3 matrix through the determinant and adjugate identity with stability checks. Random Number Generator Generate bounded whole numbers with optional uniqueness for simulations and classroom exercises. Dice Roller Roll one or more equal-sided dice and show every roll, the total, and the average. Factor and Prime Factorization Calculator List the positive factors and prime factorization of a nonzero integer. Common Factor Calculator Find the greatest common factor and every positive factor shared by a list of integers. Rounding Calculator Round a number to decimal places with explicit half-up, half-even, floor, ceiling, or toward-zero rules. Root Calculator Calculate real nth roots, including odd roots of negative values. Exponent Calculator Evaluate a real base raised to a real exponent with finite-domain validation. Ratio Calculator Solve the missing fourth term in a:b = c:x and show the equivalent ratio. 2x2 Matrix Calculator Calculate the determinant or inverse of a two-by-two matrix with the defining formula shown. Big Number Calculator Perform exact signed-integer arithmetic without converting large inputs to floating-point numbers. Long Division Calculator Divide signed whole numbers exactly and continue the quotient to a requested number of decimal places.

Average, Median, and Summary Calculator Summarize a numeric list with its arithmetic mean, median, sum, count, minimum, and maximum. Standard Deviation and Variance Calculator Measure data spread using population or sample standard deviation, with variance and mean. Independent Events Probability Calculator Find the probabilities of both, either, exactly one, or neither of two independent events. Combinations Calculator Count unordered selections of r distinct items from n items without replacement. Z-Score Calculator Express an observation's distance from a mean in standard-deviation units. Permutations Calculator Count ordered arrangements of r distinct items chosen from n. Five-Number Summary and Outliers Minimum, quartiles, median, maximum, IQR, and outlier fences for a data list. Normal CDF (Area Below z) Cumulative standard-normal probability for a z-score, accurate to about 1e-7. Confidence Interval for a Mean Two-sided z-interval for a population mean from sample mean, sd, and size. Correlation Coefficient (r) Pearson correlation between two equal-length numeric lists. Binomial Probability Exact and cumulative probabilities for a fixed number of independent trials. Confidence Interval for a Proportion Wald 95/90/99% interval for a population share from successes and trials. Sample Size for a Mean Respondents needed to hit a margin of error at 90/95/99% confidence. Least-Squares Regression Line Slope, intercept, and fitted equation for paired data. Poisson Probability Exact and cumulative probabilities for counted events at a known average rate. Expected Value (Discrete) Mean outcome of a gamble or lottery from values and probabilities. Sample Size for a Proportion Estimate how many observations a survey needs for a target proportion margin of error and confidence level. Summary Statistics Calculator Find the count, mean, median, mode, and range of a numeric list. Variance and Standard Deviation Calculator Calculate population and sample variance and standard deviation from a numeric list. Binomial Probability Calculator Find the probability of exactly k successes in n independent trials with a fixed success probability. Poisson Probability Calculator Calculate the probability of exactly k events for a Poisson process with a known mean rate. Conditional Probability Calculator Calculate the probability of an event given another event from their joint and conditioning probabilities. Coefficient of Determination Calculator Square a correlation coefficient to express the proportion of linear variation represented by the fitted relationship. Birthday Collision Probability Calculator Calculate the probability that at least two people share a birthday under a uniform-day model. Weighted Average Calculator Calculate a weighted average from comma-separated values and matching nonnegative weights. Moving Average Calculator Calculate simple moving averages from a comma-separated sequence and a selected window size. Acceptance Rate Calculator Calculate acceptance and rejection percentages from the number accepted and the total number of applications or trials. Cohen's d Effect Size Calculator Calculate the standardized mean difference between two independent groups using pooled sample standard deviation. Class Width Calculator Calculate equal histogram class width from a lower boundary, upper boundary, and number of classes. Six-Sided Dice Sum Probability Calculator Calculate the exact probability of a target sum when rolling a selected number of fair six-sided dice. 90% Mean Confidence Interval Calculator Calculate a normal-approximation 90% confidence interval for a sample mean from standard deviation and sample size. 95% Mean Confidence Interval Calculator Calculate a normal-approximation 95% confidence interval for a sample mean from standard deviation and sample size. 99% Mean Confidence Interval Calculator Calculate a normal-approximation 99% confidence interval for a sample mean from standard deviation and sample size. Absolute and Relative Uncertainty Calculator Calculate relative and percentage uncertainty from a measured value and an absolute uncertainty. Classification Accuracy Calculator Calculate accuracy from correct classifications and total evaluated cases. Independent AND Probability Calculator Calculate the probability that two independent events both occur. One-Way ANOVA F Statistic Calculator Calculate between-group and within-group mean squares and the one-way ANOVA F statistic from summary sums of squares and degrees of freedom. Ascending Numeric Order Calculator Parse a short comma- or space-separated list of numbers and return it in ascending order. Bayes Theorem Posterior Probability Calculator Calculate a posterior probability from prior probability, sensitivity, and specificity. Benford First-Digit Probability Calculator Calculate the expected first-digit probability under Benford's logarithmic distribution. Binomial Exact Probability Calculator Calculate the probability of exactly k successes in n independent Bernoulli trials. Five-Number Box Plot Summary Calculator Calculate minimum, first quartile, median, third quartile, and maximum from a numeric list using Tukey hinges. Central Limit Theorem Standard Error Calculator Estimate the standard error and normal-approximation interval for a sample mean. Chebyshev Theorem Coverage Calculator Calculate the guaranteed minimum fraction within k standard deviations of a mean. Exact Coin-Flip Count Probability Calculator Calculate the probability of exactly a selected number of heads in fair coin flips. Confusion Matrix Metrics Calculator Calculate accuracy, precision, recall, specificity, and F1 score from a binary confusion matrix. Normal Continuity Correction Calculator Apply a half-unit continuity correction to a discrete count boundary and convert it to a normal z score. Decile from Numeric Data Calculator Estimate a selected decile from a numeric list using linear interpolation of the sorted positions. Custom Dice Sum Probability Calculator Calculate an exact target-sum probability for a selected number of fair dice with a selected number of sides. Two-Proportion A/B Test Z-Score Calculator Compare two independent proportions with a pooled two-proportion z statistic. Beta Distribution Density Calculator Evaluate the beta probability density and mean for a selected shape pair and value. Chi-Square Goodness-of-Fit Statistic Calculator Calculate a chi-square goodness-of-fit statistic and degrees of freedom from observed and expected counts. Coin Flip Streak Probability Calculator Calculate the probability of seeing at least one run of consecutive heads in fair coin flips. One-Way ANOVA Degrees of Freedom Calculator Calculate total, between-group, and within-group degrees of freedom from sample size and group count. Descriptive Statistics Summary Calculator Calculate population-style mean, median, range, variance, and standard deviation for a finite numeric list. Independent Groups Standardized Difference Calculator Calculate the standardized mean difference between two independent groups using a pooled standard deviation. Independent Measurement Error Propagation Calculator Estimate propagated absolute uncertainty for addition, subtraction, multiplication, or division of two measured values. First Quartile Calculator Calculate the 25th percentile from a finite numeric list using linear interpolation on sorted positions. Grouped Frequency Distribution Calculator Group a finite numeric list into equal-width bins and count the values in each interval. Decimal Odds Implied Probability Calculator Convert decimal odds greater than one into implied probability and percentage. Normal Distribution Point Calculator Calculate a z score, density, and cumulative probability for a point under a normal distribution. Sample Proportion and Standard Error Calculator Calculate a sample proportion and its simple binomial standard error from successes and trials. Two-Sided Normal Z P-Value Calculator Calculate the two-sided standard-normal tail probability associated with a z statistic. Mean Median and Mode Calculator Calculate mean, median, and repeated-value mode information for a finite numeric list. Probability to Odds Calculator Convert a probability below one into odds in favor and log-odds. IQR Outlier Fence Calculator Calculate Tukey outlier fences and classify one value using first and third quartiles. Poisson Exact Count Probability Calculator Calculate the exact probability of observing a selected event count under a Poisson rate model. Mean Squared Error and RMSE Calculator Calculate mean squared error and root mean squared error from equal-length actual and predicted lists. Relative and Percentage Error Calculator Calculate signed relative error and absolute percentage error from an actual value and a nonzero reference. Bertrand Box Conditional Probability Calculator Calculate the probability that a selected coin is gold on the other side after observing a gold face in a three-box paradox model. Boy-or-Girl Conditional Probability Calculator Calculate the probability that both children are girls after a selected at-least-one-girl observation model. Cubic Prediction Polynomial Calculator Evaluate a cubic prediction equation from four supplied coefficients and an input x value. Decimal Odds Probability and Payout Calculator Convert decimal odds to implied probability and calculate total payout and net profit from a stake. Exponential Model Prediction Calculator Evaluate an exponential prediction model from a starting value, continuous rate, and elapsed time. False Positive and Predictive Value Calculator Calculate false-positive rate, positive predictive value, and false discovery rate from prevalence, sensitivity, and specificity. Five-Star Rating Summary Calculator Calculate review count, average star rating, and share of four-or-five-star ratings from star counts. Index of Qualitative Variation Calculator Calculate the index of qualitative variation from category counts. Lower Outlier Fence Calculator Calculate interquartile range and the lower Tukey outlier fence from first and third quartiles. Matthews Correlation Coefficient Calculator Calculate the Matthews correlation coefficient from binary-classification confusion counts. McNemar Paired Proportion Statistic Calculator Calculate the continuity-corrected McNemar chi-square statistic from discordant paired counts. Monty Hall Switching Probability Calculator Calculate stay and switch win probabilities for a generalized Monty Hall game with one prize door. Two-Game Mixed Win-Rate Calculator Calculate the expected win probability for a random mix of two independent games. Proportion Point Estimate Calculator Calculate a sample proportion point estimate and its complement from successes and trials. Process Capability Cp and Cpk Calculator Calculate Cp and Cpk from specification limits, process mean, and process standard deviation. Rayleigh Distribution PDF and CDF Calculator Calculate the probability density, cumulative probability, mean, and standard deviation for a Rayleigh value. Prediction Residual Calculator Calculate signed residual, absolute residual, and squared residual from observed and predicted values. Relative Standard Deviation Calculator Calculate relative standard deviation as a ratio and percentage from standard deviation and mean. Sampling Error Difference Calculator Calculate the signed sampling error between a sample proportion and a supplied population proportion. Expected Risk and Loss Calculator Calculate expected loss from event probability and loss amount, with the complement probability shown. Percentile from a Data List Calculator Estimate a percentile from a sorted or unsorted numeric list using linear interpolation between observations. Interquartile Range Calculator Calculate the interquartile range and midhinge from supplied first and third quartiles. Upper Tukey Fence Calculator Calculate the upper exploratory fence from first and third quartiles using the 1.5-IQR convention. Percentile Rank Calculator Estimate the percentile rank of a target value within a numeric data list, including a transparent tie convention. Trimmed Mean Calculator Calculate a two-sided trimmed mean by removing the same percentage of low and high observations. Mean Absolute Deviation Calculator Calculate the arithmetic mean and the average absolute distance from that mean. Coefficient of Variation Calculator Calculate relative spread by dividing population standard deviation by the absolute arithmetic mean. Standard Error of the Mean Calculator Calculate the standard error and variance of a sample mean from a standard deviation and sample size. Pooled Variance Calculator Calculate pooled variance and pooled standard deviation for two independent groups. Welch Degrees of Freedom Calculator Calculate the Welch–Satterthwaite degrees of freedom for an unequal-variance two-sample mean comparison. Discrete Expected Value Calculator Calculate the expected value and variance of a discrete distribution from paired outcomes and probabilities. Binomial Mean and Variance Calculator Calculate the expected successes, variance, and standard deviation for a binomial model. Geometric Waiting-Time Mean Calculator Calculate the mean and variance of the number of trials until the first success in a geometric model. Odds Ratio from a Two-by-Two Table Calculator Calculate the odds ratio and its natural logarithm from four cells in a two-by-two comparison table. Relative Risk from a Two-by-Two Table Calculator Calculate event risk in two groups and their relative risk from a two-by-two table. Pearson Median Skewness Calculator Calculate Pearson’s second skewness coefficient from the mean, median, and standard deviation. Pooled Two-Sample Degrees of Freedom Calculator Calculate the pooled degrees of freedom for an independent two-sample comparison. Glass’s Delta Effect Size Calculator Calculate Glass’s delta using the control-group standard deviation as the reference scale. Empirical Rule Interval Calculator Calculate one-, two-, and three-standard-deviation intervals and their normal-model coverage percentages. Independent Sum Error Propagation Calculator Calculate the combined absolute and relative uncertainty for a sum or difference of two measured quantities. F-Statistic Calculator Calculate the ratio of two entered variances for a simple F-statistic scenario. Joint Probability Calculator Calculate independent and conditional joint probabilities from event A and event B inputs. Lognormal Distribution Calculator Calculate lognormal density, cumulative probability, reliability, mean, and median from a median scale and shape parameter. Margin of Error Calculator Calculate a normal-approximation margin of error from a critical value, standard deviation, and sample size. Binomial Normal Approximation Calculator Estimate an inclusive binomial count probability using a normal approximation with an optional continuity correction. Sampling Distribution Probability Calculator Calculate the probability that a sample mean falls between two bounds under a normal sampling-distribution assumption. One-Sample Normal Power Calculator Estimate one-sided or two-sided normal-test power from an effect, standard deviation, significance level, and sample size. Three Independent Events Probability Calculator Calculate the probability that three independent events all occur, at least one occurs, or none occurs. Quadratic Regression Calculator Fit a least-squares quadratic y=a+bx+cx² to paired data and evaluate the fitted equation at a target x. Relative Frequency Calculator Convert an observed count into a relative frequency, percentage, and complement within a stated total. Shannon Entropy Calculator Calculate Shannon entropy in bits and min-entropy from a finite probability distribution. Population Skewness Calculator Calculate the Fisher-Pearson population skewness of a finite list of observations. One-Sample t-Statistic Calculator Calculate a one-sample t statistic, standard error, and degrees of freedom from summary statistics. Two-Sample t-Test Statistic Calculator Calculate a two-sample t statistic using either a pooled-variance or Welch unequal-variance standard error. Mann-Whitney U Statistic Calculator Rank two independent samples, calculate the Mann-Whitney U statistics, and show a normal-approximation z score. Weibull Distribution Calculator Calculate Weibull density, cumulative probability, reliability, and mean from shape, scale, and evaluation value. Youden's J Index Calculator Calculate Youden's J from sensitivity and specificity for a binary classification threshold. One-Sample z-Test Statistic Calculator Calculate a one-sample z statistic and two-sided normal p-value when a population standard deviation is supplied. False Positive Base-Rate Calculator Calculate positive predictive value and negative predictive value from prevalence, sensitivity, and false-positive rate. Normal Critical Value Calculator Calculate the two-sided standard-normal critical value for an entered confidence level. Simpson Diversity Index Calculator Calculate Simpson concentration and Gini-Simpson diversity from category counts. Fisher's Exact Test Calculator Calculate an exact two-sided Fisher probability for a 2×2 contingency table with fixed margins. Grouped Data Standard Deviation Calculator Estimate weighted mean and population or sample standard deviation from class midpoints and frequencies. Midrange Calculator Calculate the minimum, maximum, range, and midrange of a numeric data list. Moneyline Odds Calculator Convert a positive or negative moneyline into implied probability, decimal odds, and profit on a fixed stake. OR Probability Calculator Calculate the probability of at least one of two events, exactly one event, and neither event from an overlap. Quartic Regression Calculator Fit a fourth-degree least-squares polynomial to paired data and evaluate it at a target value. Relative Standard Error Calculator Calculate the standard error and relative standard error of a sample mean from a data list. Sum of Squares Calculator Calculate the squared-deviation total, mean squared deviation, and root-mean-square distance from a reference value. Two-Envelope Scenario Calculator Evaluate a transparent two-envelope switching scenario under explicit up/down ratios and a stated probability. Upper Control Limit Calculator Calculate center, upper, and lower three-sigma-style limits for a sample-mean control chart. Raw Score Calculator Convert a z-score into a raw score using a supplied mean and standard deviation. Fractional Odds Calculator Convert fractional odds into decimal odds, implied probability, and profit on a fixed stake. Roulette Payout and House Edge Calculator Estimate win probability, payout, expected net result, and house edge for straight-up or even-money roulette bets. Sample Proportion Probability Calculator Calculate the normal-approximation probability that a sample proportion falls between two bounds. Pie Chart Angle Calculator Convert a category count within a total into a percentage and the central angle for a pie-chart slice. Range Calculator Calculate the minimum, maximum, and total range of a numeric data list. Two-Set Venn Count Calculator Calculate A-only, B-only, union, overlap, and neither counts for two sets inside a stated universe. Five-Number Summary Calculator Sort five observations and report the minimum, first quartile, median, third quartile, and maximum. Combinations Without Repetition Calculator Count how many unordered groups of a chosen size can be selected from a finite set without repeating an item. Mean Confidence Interval Calculator Build a two-sided mean confidence interval from a sample mean, standard deviation, sample size, and supplied critical value. Range and Relative Dispersion Calculator Calculate the range, midrange, and coefficient of range from a positive minimum and maximum. Interquartile Spread (IQR) Calculator Find the interquartile range, midhinge, and quartile spread from the first and third quartiles. Mean Absolute Deviation for Five Values Calculate the mean, mean absolute deviation, and largest absolute deviation for five observations. Median Calculator for Five Values Sort five numeric values and calculate their median, mean, and distance between the extreme values. Minimum, Maximum, and Range Calculator Calculate the span, midpoint, and endpoint ratio from a minimum and maximum observation. Mode Calculator for Five Values Find the unique most frequent value in a five-observation dataset and report its frequency and share. Permutation Calculator Count ordered selections of r distinct items from n available items without repetition. Pooled Standard Deviation Calculator Combine two sample standard deviations using their degrees of freedom to estimate a common pooled spread. Population Variance Calculator Calculate the population mean, population variance, standard deviation, and root-mean-square value for five values. Probability from Favorable Outcomes Convert favorable and total equally likely outcomes into probability, percentage, complement, and odds. Quartile Calculator for Nine Values Sort nine observations and calculate Q1, median, Q3, interquartile range, and the quartile midhinge. Sensitivity Calculator Calculate sensitivity, miss rate, and the number of actual positive cases from true positives and false negatives. Specificity Calculator Calculate specificity, false-positive rate, and the number of actual negative cases from true negatives and false positives. Sensitivity and Specificity Calculator Summarize all four cells of a binary classification table with sensitivity, specificity, accuracy, and prevalence. Sampling Standard Error Calculator Calculate the standard error of a sample mean and an illustrative 95% normal-approximation margin. Two-Dice Sum Probability Calculator Calculate the number of ordered outcomes, probability, percentage, and complement for a target sum from two fair six-sided dice. Measurement Uncertainty Calculator Convert an absolute measurement uncertainty into relative uncertainty, percent uncertainty, and an interval around a measured value. Journal Impact Factor Arithmetic Calculator Calculate the two-year citation rate used in a journal impact-factor style summary from citations and scholarly items, while keeping the metric's scope clear. Third Quartile Calculator Sort a raw dataset and calculate its third quartile, median, first quartile, and interquartile range using a stated median-of-halves convention. Upper and Lower Outlier Fence Calculator Calculate the lower and upper Tukey-style outlier fences from Q1, Q3, and an entered IQR multiplier. Sample or Population Variance Calculator Calculate variance and standard deviation from a pasted dataset while keeping the population or sample divisor explicit. Standard Deviation and Standard Error from Data Calculate a sample standard deviation, standard error of the mean, and relative standard error from raw observations. Histogram Bin Count Calculator Group raw numeric values into equal-width histogram bins and report counts, relative frequencies, and density values. Stem-and-Leaf Plot Calculator Sort raw values into a text stem-and-leaf display while retaining the individual observations. Frequency Polygon Point Calculator Convert class midpoints and frequencies into frequency-polygon points, total frequency, and a grouped weighted mean. Dot Plot Frequency Table Calculator Count repeated values in a raw dataset and produce a sorted dot-plot table with frequencies and proportions. Ordering Numbers Calculator Sort a pasted list from least to greatest and greatest to least, and report the center and endpoints. Pie Chart Percentage Calculator Calculate a category's share, percentage, and pie-slice angle from a category count and total count. Wilcoxon Rank-Sum Statistic Rank two independent samples, calculate the Wilcoxon rank-sum and U statistics, and show a large-sample normal approximation. Inverse Normal Distribution Calculator Find the normal-distribution value at a chosen cumulative percentile from a mean and standard deviation. Post-Test Probability Calculator Use prevalence, sensitivity, and specificity to estimate positive and negative post-test probabilities with Bayes' theorem. One-Sample z Hypothesis Test Calculator Calculate a one-sample z statistic and tail-specific p-value when the population standard deviation is supplied. Least-Squares Linear Regression Calculator Fit a straight line to paired observations and report the slope, intercept, prediction, correlation, and explained variation. Password Combination Calculator Count the exact number of passwords possible from an alphabet size and length, with or without character reuse. Fair Coin Heads Probability Calculator Calculate the probability of an exact or at-least number of heads in repeated fair-coin flips, plus the expected count and spread. Expected Dice Average Calculator Calculate the expected value, variance, standard deviation, and possible range for a sum of fair identical dice. Pie Chart Slice Calculator Turn a list of category values into totals, percentages, and central angles for a complete pie chart. Bertrand Chord Probability Model Calculator Compare the classic probabilities for a chord longer than an inscribed equilateral-triangle side under three explicit random-chord models. Scatter Plot and Linear Regression Calculator Summarize paired x and y data with a correlation coefficient, least-squares line, fitted values, and a transparent prediction. Pearson Correlation Calculator Calculate Pearson’s r, r², means, and supporting sums from paired X and Y observations entered as comma-separated values. Exponential Growth and Decay Calculator Project a positive starting value under discrete compounding or continuous exponential growth and display the change and doubling time. Polynomial Regression Calculator Fit an ordinary least-squares polynomial of degree 1 to 5 to paired observations and report the equation, R², and RMSE. Gender Pay Gap Percentage Calculator Calculate an unadjusted pay gap, comparison-group pay share, and absolute difference from two user-entered earnings figures without bundling stale country data. Lottery Match Probability Calculator Calculate the chance of meeting a chosen lottery match threshold from a pool, ticket size, draw size, and number of tickets without assuming a particular country's game rules. Inverse Standard Normal (z Quantile) Finds the z-score with a given left-tail area under the standard normal curve. Chi-Square Goodness of Fit Tests counts against expected counts with the Pearson chi-square statistic. Empirical Rule Bands 68-95-99.7% intervals from mean and standard deviation. Confidence Interval for a Mean (t) t-interval for the mean when sigma is unknown. Bayes Flip P(A|B) Flips P(B|A) into P(A|B) from the base rate and evidence rate. Root Mean Square Calculate the root mean square of a bounded list of numeric values. Geometric Mean Calculate the geometric mean of a list of positive values using logarithmic accumulation for stability. Harmonic Mean Calculate the harmonic mean of a list of positive values. Bonferroni Correction Calculate a Bonferroni-adjusted significance threshold and adjusted p-value for multiple comparisons. Coefficient of Variation Calculate the sample standard deviation relative to a positive sample mean. Sample Covariance Calculate the sample covariance of two equal-length paired data sets. Spearman Rank Correlation Calculate Spearman's rank correlation for two paired data sets, including average ranks for ties. Geometric Distribution Calculate the probability that the first success occurs on a selected trial and the cumulative probability by that trial. Negative Binomial Distribution Calculate the probability of observing a selected number of failures before a specified number of successes. Median Absolute Deviation Calculate the median and raw median absolute deviation of a numeric sample. Combinations With Repetition Count unordered selections of a fixed size from reusable types, where selecting the same type more than once is allowed. Permutations With Repetition Count ordered sequences of a fixed length from reusable types, where each position may use any type again. Hypergeometric Distribution Calculate an exact and cumulative probability for successes drawn without replacement from a finite population. Continuous Uniform Distribution Evaluate the density and cumulative probability of a continuous uniform variable on a finite interval, with its mean and variance. Exponential Distribution Evaluate the density, cumulative probability, survival probability, mean, and variance of an exponential waiting-time model.

Running Pace and Speed Calculator Calculate average running pace and speed from distance and elapsed time. Bowling Average Calculator Calculate a simple bowling average from total runs and completed innings or games. Cycling Cadence Calculator Estimate wheel speed and crank cadence from road speed, wheel diameter, and a wheel-to-crank ratio. Batting Strike Rate Calculator Calculate a cricket batting strike rate from runs scored and legal balls faced. Bicycle Gear Ratio Calculator Calculate bicycle gear ratio and mechanical distance per crank revolution from front and rear sprocket teeth. Elo Rating Update Calculator Calculate expected score and a new Elo rating from two ratings, a K-factor, and an entered match result. Cycling Power Estimate Estimate steady cycling power from mass, speed, road grade, rolling resistance, and aerodynamic drag inputs. Ape Index Calculator Calculate the difference and ratio between arm span and height as a simple body-proportion measure. Vertical Jump Requirement Calculator Calculate the vertical jump required to clear a target height from standing reach and a desired clearance margin. Bicycle Frame Size Estimate Estimate a bicycle frame size from inseam length and a selected road or mountain-bike multiplier. E-Bike Range Estimate Estimate electric-bike travel range from battery energy, usable efficiency, reserve, and energy consumption per distance. Fishing Reel Line Capacity Calculator Estimate line length on a cylindrical spool from outer diameter, core diameter, spool width, and line diameter. Bicycle Speed from Cadence Calculator Calculate bicycle speed from wheel diameter, cadence, and a wheel-to-crank distance ratio. Hiking Time with Elevation Calculator Estimate hiking time from horizontal distance, base speed, elevation gain, and a supplied climbing speed. Displacement Hull Speed Calculator Estimate a traditional displacement-hull speed from waterline length using a supplied hull-speed coefficient. Walking Stride Length Calculator Calculate average stride length from walking distance and step count, with a metres-per-step result. Steps to Distance Calculator Estimate walking distance from step count and an explicitly supplied average stride length. Pool Table Room Size Calculator Calculate minimum room length, width, and area from table dimensions and cue clearance on every side. 0–60 Acceleration Calculator Estimate average acceleration and travel distance for a 0-to-speed run from elapsed time under a constant-acceleration model. Bench Press One-Rep-Max Estimate Estimate a bench-press one-repetition maximum from a lifted load and completed repetitions using the Epley relation. Bicycle Chain Length Estimate Estimate bicycle chain length in chain pitches from center distance and front and rear sprocket tooth counts. Fish Weight Estimate from Length and Girth Estimate fish mass from entered length, girth, and a visible species or unit coefficient. Generic Game Score Calculator Add scored events with entered point values to calculate a transparent team or game score. Pace and Speed Calculator Calculate average pace and speed from a distance, elapsed time, and the distance unit you use. 5K Pace Calculator Convert a 5-kilometre finish time into average kilometre and mile pace and speed. Half-Marathon Pace Calculator Calculate average pace and speed for a half-marathon from a finish time. Marathon Pace Calculator Calculate average marathon pace and speed from a full-marathon finish time. Cycling Pace and Moving Speed Calculator Separate moving time from stop time to estimate cycling pace, moving speed, and elapsed speed. Bike Cadence and Speed Calculator Estimate bicycle speed from wheel diameter, pedalling cadence, and wheel-to-crank gear ratio. Race Time Predictor Project a target race time from a completed distance and time using an adjustable endurance exponent. Training Pace Calculator Estimate a target training pace from a reference performance, target distance, and selected effort percentage. Walking Calorie Estimate Estimate walking energy from body mass, duration, speed, and uphill or downhill grade using a transparent exercise equation. Running Calorie Estimate Estimate running energy from body mass, distance, and a user-selected terrain factor. Jump-Rope Calorie Estimate Estimate jump-rope energy from body mass, duration, and a selected rope-skipping intensity. Stair-Climbing Energy Calculator Estimate the energy needed to raise a body through a number of stair flights using gravitational work and an efficiency assumption. Steps to Calories Estimate Convert steps into an estimated walking distance and energy using stride length and an explicit energy-per-distance assumption. Steps to Miles and Kilometres Calculator Estimate walking distance from a step count and average stride length in both kilometres and miles. Hiking Time Estimate Estimate hiking time from horizontal distance, elevation gain, terrain factor, and planned rest time. Triathlon Time Calculator Add swim, bike, run, and transition estimates to plan a total triathlon time. Swimming Time Calculator Estimate total swim-session time from distance, pace per 100 metres, and planned rest intervals. Cycling Power Zones Calculator Build cycling power zones from functional threshold power using a selectable five-zone or seven-zone percentage scheme. Target Heart-Rate Range Calculator Estimate a heart-rate range with the heart-rate-reserve method from age, resting pulse, and two intensity percentages. Heart-Rate Recovery Calculator Calculate the one-minute heart-rate drop and normalized recovery from resting, peak, and post-exercise heart rates. Poker Drawing Odds from Outs Calculate the chance of hitting at least one out by the next one or two cards from unseen-card count. Poker Expected Value of a Call Estimate the expected profit or loss of a poker call from win, tie, pot, and call-cost assumptions. Fielding Independent Pitching Calculate a baseball pitcher's FIP-style estimate from home runs, walks, hit batters, strikeouts, innings, and a chosen league constant. NFL-Style Passer Rating Calculator Calculate the NFL-style passer rating from attempts, completions, passing yards, touchdowns, and interceptions. Cricket Net Run Rate Calculator Calculate a cricket team's net run rate from runs scored, runs conceded, and the legal balls in each innings sample. MET-Minutes per Week Calculator Estimate weekly MET-minutes from activity intensity, session duration, and sessions per week, with time-equivalent views. Cooper 1.5-Mile VO₂ Max Estimate Estimate VO₂ max from a timed 1.5-mile run or walk using the Cooper Institute field-test equation. Race Split Planner Build an even split schedule from a target distance, finish time, and split length, including the final partial split when the distances do not divide evenly. Rowing Erg Pace and Watts Calculator Calculate rowing-erg work time, 500-metre split pace, average speed, estimated watts, and total session time for repeated intervals with optional rest. Cycling Breakaway Gap Planner Estimate how a speed difference changes a cycling breakaway's physical gap over a selected time horizon and when a target gap could be reached. Bench Press Pyramid Volume Planner Build a transparent ascending or descending bench-press percentage pyramid from a user-entered one-rep maximum, set count, repetitions, and percentage step. Ski Length Range Scenario Calculator Create a transparent ski-length range from height, ability, terrain, and editable shorter- and longer-end adjustments instead of presenting one universal ski size. Tennis Ball Inventory Planner Estimate match balls, practice balls, replacement allowance, and cans needed for a tennis event or training block using editable event rules. Cricket Follow-On Lead Calculator Check a first-innings lead against the selected match duration and show the shortfall or margin for a follow-on option. Bruce Protocol METs Estimate Estimate treadmill workload, oxygen uptake, and METs for a selected stage of the standard Bruce exercise-testing protocol. Women’s Heptathlon Points Calculator Estimate points for the seven events in a women’s heptathlon and show track, field, event, and total scores. Wilks Powerlifting Score Calculator Calculate the historical Wilks coefficient and bodyweight-adjusted powerlifting score from category, body weight, and total. 5/3/1 Training-Max Percentage Calculator Plan three working sets from a 5/3/1 training max, selected week, and equipment rounding increment. Baseball Magic Number Calculator Calculate the standings combination of wins and opponent losses needed to clinch a baseball goal from the loss-column gap and games remaining. Human Punch Force Estimate Estimate average model force, impulse, velocity change, and kinetic energy from effective striking mass, acceleration, and contact time. Age-Graded Running Calculator Compare a runner's entered race time with an age-and-category reference standard, then show age grade, time gap, pace, and speed without pretending to supply an official table. Anaerobic Threshold Field-Test Calculator Estimate a threshold heart rate and pace from a controlled time trial, show heart-rate drift, and display transparent planning screens with clear limits. Triathlon Finish-Time Breakdown Calculator Add swim, bike, run, and transition times for a sprint, standard, or custom course and show total time, discipline shares, pace, and speed. Magic Mile Race-Time Predictor Project a target running time from a measured mile using a transparent distance-power model, with target pace, speed, and model cost shown together. Triathlon Training-Load Planner Project weekly training hours through a build and taper using explicit progression, reduction, and session-count inputs, with a transparent workload summary. Cricket Rain-Interrupted Target Calculator Apply supplied first- and second-innings resource percentages to estimate a revised cricket target, while keeping the resource-ratio method separate from official professional tables. ICC T20 Team Ranking Points Calculator Project one team's match points and updated rating from two supplied team ratings, a result, and the number of matches already represented in the average. Windsurfing Apparent-Wind and Sail-Force Calculator Resolve true wind and board motion into apparent wind, dynamic pressure, and a transparent sail-force screen for a simplified windsurfing physics scenario. Heart-Rate Energy Estimate Calculator Estimate exercise energy from average heart rate, body mass, age, equation branch, and duration using a transparent population-derived heart-rate model. Snow-Shoveling Energy Calculator Estimate total and active-above-rest energy for manual snow shoveling from body mass, duration, and moderate or vigorous activity intensity. Race Time Improvement Calculator Apply a chosen percentage improvement to a current race time and show the faster target, seconds saved, and equivalent minutes saved. Goalkeeper Save Percentage Calculator Calculate save percentage, shots not saved, concession percentage, and shots faced per save from a defined shot sample. Fat-Burning Heart-Rate Zone Calculator Compare percentage, Karvonen heart-rate-reserve, and Zoladz reference ranges from age, resting heart rate, and a maximum-heart-rate choice. Scuba Neutral-Buoyancy Ballast Estimate Estimate the ballast mass needed for a simplified neutral-buoyancy scenario from diver, equipment, suit, cylinder, gas, and water-density inputs. Kiteboarding Apparent Wind and Force Screen Estimate apparent wind, aerodynamic dynamic pressure, lift, drag, and resultant kite force from wind, rider speed, angle, kite area, and coefficients. Batting Average Calculate a baseball hitter's batting average from hits and at-bats. On-Base Percentage Calculate baseball on-base percentage from hits, walks, hit-by-pitches, at-bats, and sacrifice flies. Slugging Percentage Calculate baseball slugging percentage from hit-type counts and at-bats. On-Base Plus Slugging Add already-calculated on-base and slugging percentages to obtain OPS. Earned Run Average Calculate a baseball pitcher's earned-run average from earned runs and recorded outs. Baseball WHIP Calculate walks plus hits per inning pitched from a baseball pitching line. Fielding Percentage Calculate a baseball fielder's fielding percentage from putouts, assists, and errors. Effective Field Goal Percentage Calculate basketball effective field goal percentage while giving made three-pointers extra shot value. True Shooting Percentage Estimate basketball true shooting percentage from points, field-goal attempts, and free-throw attempts. Faceoff Win Percentage Calculate a hockey player's faceoff win percentage from wins and losses. Goalie Save Percentage Calculate a hockey goaltender's save percentage from saves and goals allowed. Goals-Against Average Calculate a hockey goaltender's goals-against average from goals allowed and minutes played. Winning Percentage Calculate a team's or player's win rate from wins and losses.

Age in Completed Years and Days Calculate completed calendar years and exact elapsed days between a birth date and a chosen date. Date Difference Calculator Count elapsed or inclusive calendar days between dates, with whole weeks and leftover days. Add or Subtract Calendar Days Move forward or backward by a whole number of days while correctly crossing months, years, and leap days. Time Duration Calculator Find hours and minutes between two clock times on the same day or the following day. Work Hours and Unpaid Break Calculator Calculate net paid hours for a shift and a chosen number of identical shifts after unpaid breaks. Pregnancy Due Date (Naegele's Rule) Estimate a due date as 280 days after the first day of the last menstrual period. Business Days Calculator Count weekdays between two dates with explicit endpoint rules and your own holiday list. Day of Week Calculator Find the weekday and ISO weekday number for any valid Gregorian date from year 1 through 9999. Age Between Dates Calculator Calculate completed years and total elapsed days between a birth date and a chosen date. Counted Hours and Minutes Calculator Convert a number of shifts and hours per shift into total hours and minutes, with an optional unpaid break. Add Time Durations Calculator Add two durations and normalize the total into days, hours, minutes, and seconds without wrapping at midnight. Birth Date from Death Date and Exact Age Calculator Work backward from a death date and an entered completed age in years, months, and days using explicit Gregorian calendar arithmetic for genealogy and historical records. Palindrome Date Checker Check whether a date reads the same forward and backward in a selected numeric format and search for the next matching date. Ovulation and Fertile Window Estimate Estimate a next period, ovulation date, and fertile window from cycle assumptions. Time Zone Offset Converter Convert a date and time between two fixed UTC offsets without pretending to know city daylight-saving rules.

Flooring Area and Waste Calculator Estimate rectangular floor area, planned waste, order area, and package count. Paint Quantity Calculator Estimate paint volume and whole-can count from surface area, coats, coverage, and can size. Concrete Volume Calculator Estimate rectangular concrete volume with an explicit waste allowance. Air-Conditioning Tonnage Estimate Estimate nominal cooling tons from a cooling load stated in BTU per hour. Carpet Quantity Calculator Estimate net floor area and carpet quantity after an entered waste allowance. Asphalt Volume and Mass Calculator Estimate asphalt volume and mass for a rectangular paving area with a waste allowance. Brick Quantity Calculator Estimate the number of rectangular brick faces needed for a wall after an entered waste allowance. Concrete Weight Calculator Estimate concrete mass from volume and an entered density. Elevation Grade Calculator Calculate slope grade percentage and angle from vertical rise and horizontal run. Floor Area Ratio Calculator Calculate floor area ratio from total building floor area and site area. Air Changes to CFM Calculator Estimate cubic feet per minute from room volume and desired air changes per hour. Rectangular Fence Length Calculator Calculate the perimeter of a rectangular enclosure and add an optional waste allowance. Board and Batten Wall Estimate Estimate board count, batten count, and covered wall area for a rectangular board-and-batten surface with a waste allowance. Deck Board Quantity Calculator Estimate deck board count and material area from deck dimensions, board width, gap, and waste allowance. French Drain Trench Volume Calculator Estimate trench volume, pipe length, and drainage-rock volume from rectangular trench dimensions and a rock-fill fraction. Air Changes per Hour Calculator Calculate air changes per hour from room volume and average ventilation flow, with metric and cubic-foot outputs. Circular Arch Opening Calculator Calculate the radius, opening area, and curved arch length from a circular-segment opening width and rise. Aluminum Plate Weight Calculator Calculate the volume and estimated weight of a rectangular aluminum plate from dimensions and density. Baluster Count and Spacing Calculator Estimate the number of balusters needed to keep equal clear gaps below a selected maximum across an opening. Bolt Circle Layout Calculator Calculate radius, angular spacing, and the first bolt coordinate for a regular bolt circle. Bolt Torque from Force Calculator Calculate torque from applied force, lever-arm length, and the angle between them. Open Belt Length Calculator Estimate the length of an open belt from pulley diameters and center distance using a standard approximate geometry relation. Concrete Column Volume and Weight Calculator Calculate volume and estimated weight for a cylindrical concrete column from diameter, height, and density. Concrete Driveway Cost Estimate Estimate concrete volume, order volume with waste, and material cost for a rectangular slab. Crushed Stone Quantity Calculator Estimate crushed-stone volume and mass for a rectangular area from dimensions, depth, density, and waste allowance. Board-on-Board Fence Board Calculator Estimate overlapping fence board count and covered area from fence length, board width, overlap, height, and waste allowance. Concrete Stair Geometry Calculator Calculate total rise, total run, slope angle, and approximate concrete volume for equal rectangular stair steps. Deck Stain Quantity Calculator Estimate stain volume from deck area, coverage rate, number of coats, and a waste allowance. Epoxy Resin Quantity Calculator Estimate epoxy volume and mass from surface area, pour thickness, density, and waste allowance. Concrete Block Wall Quantity Calculator Estimate concrete masonry units from wall area, block face dimensions, and a waste allowance. Concrete Tube Volume and Weight Calculator Calculate volume and estimated mass for a cylindrical concrete tube from diameter, height, and density. Simple Shed Material Cost Calculator Estimate a simple shed material budget from floor area, wall area, roof area, unit prices, and a waste allowance. Copper Wire Weight Calculator Calculate cylindrical copper wire volume and estimated mass from length, diameter, and density. Clearance Hole Diameter Calculator Calculate a simple clearance-hole diameter by adding a selected installation margin to a fastener diameter. Floor Joist Count and Spacing Calculator Estimate joist count and actual equal spacing for a floor length and selected maximum spacing. Tile Grout Volume Calculator Estimate grout volume from tile area, joint dimensions, tile dimensions, and a visible waste allowance. Fence Picket Count Calculator Estimate picket count and face area from fence length, picket width, gap, height, and waste allowance. Miter Angle from Corner Angle Calculator Calculate equal miter-cut angles for a symmetric joint from the total corner angle. Glass Panel Weight Calculator Estimate a rectangular glass panel's area, volume, and mass from dimensions, thickness, and density. Room Cooling Load Planning Calculator Estimate a simple air-conditioner cooling capacity from room area, a base load, and occupants. Angle of Depression Calculator Calculate the downward viewing angle from an observation height and horizontal distance. Spherical Bowl Segment Volume Calculator Estimate the volume of a spherical-cap bowl from sphere radius and cap depth. Fuel Carbon Dioxide Equivalent Calculator Estimate carbon-dioxide mass from fuel mass, carbon fraction, and an oxidation fraction. Cement Bag Quantity Estimate Estimate cement mass and bags from concrete volume, cement fraction, cement density, and bag size. Cubic Metre to Cubic Yard Calculator Convert a volume in cubic metres to cubic yards and back using the exact SI-to-US customary volume factor. Fence Post Embedment Planning Calculator Estimate underground fence-post depth from post height and a selected embedment fraction. Fence Stain Quantity Calculator Estimate stain volume from fence face dimensions, number of coats, coverage, and waste allowance. Room Heating Load Planning Calculator Estimate a simple furnace heating capacity from room area, base load, climate factor, and occupants. Flow Rate in Gallons per Minute Calculator Calculate a volumetric flow rate from volume and elapsed time and report litres per minute. Gravel Driveway Quantity Calculator Estimate gravel volume and mass from driveway dimensions, bulk density, and waste allowance. Surface Heat Loss Calculator Estimate conductive heat flow through an area from U-value and indoor-outdoor temperature difference. Euler Buckling Critical Load Calculator Estimate the ideal Euler critical load for a slender column from length, stiffness, end-condition factor, and second moment of area. Thin-Walled Hoop Stress Calculator Estimate circumferential hoop stress in a thin-walled cylindrical pressure vessel from pressure, radius, and wall thickness. Mohr’s Circle Plane-Stress Calculator Calculate the center, radius, principal stresses, and maximum in-plane shear stress for a plane-stress state. Birdsmouth Cut Planning Calculator Estimate a rafter seat-cut length from roof pitch, rafter depth, and a user-selected cut-depth fraction. Boiler Heat-Load Planning Calculator Estimate a nominal boiler input from heated volume, design temperature rise, heat-loss factor, and efficiency. Electrical Box Fill Planning Calculator Estimate required box volume from conductor, device, ground, and internal-clamp allowances supplied by the user. Chicken Coop and Run Size Planner Estimate coop floor area and outdoor run area from flock size and user-selected space allowances. Concrete Block Wall Fill Estimate Estimate block count, gross wall volume, and a user-defined void-fill volume for a block wall. Concrete Cylinder Volume Calculator Calculate concrete volume for one or more cylindrical footings, posts, or forms with a waste allowance. Concrete Slab Quantity Calculator Estimate slab concrete volume, cubic yards, and a waste-adjusted order quantity from length, width, and thickness. Countersink Depth Calculator Calculate a conical countersink depth from screw-head diameter, body diameter, and included angle. DIY Shed Cost Planning Calculator Estimate a simple shed project cost from floor, wall, and roof areas with separate material rates and waste. Door Header Length Planning Calculator Calculate a preliminary header cut length from opening width, bearing on each side, and a cutting allowance. Square Feet and Depth to Cubic Yards Calculator Convert an area in square feet and a material depth in inches into cubic yards with waste. Gallons per Square Foot Depth Calculator Convert a liquid volume spread over an area into an equivalent depth and surface loading. Gambrel Roof Surface Area Calculator Estimate two-sided gambrel roof surface area from building length and the two roof-slope segments. Round Hole Excavation Volume Calculator Estimate soil or concrete volume for repeated cylindrical holes from diameter, depth, count, and waste. Hoop House Cover and Volume Calculator Estimate cover area and interior volume for a semicylindrical hoop-house frame with optional base-wall height. Insulation Thickness and Volume Calculator Estimate insulation thickness, material volume, and waste from target R-value, conductivity, and surface area. Ladder Angle and Length Calculator Calculate the ladder angle and required ladder length from wall height and base distance. Landscape Rock Weight and Volume Calculator Estimate decorative rock volume, mass, and tonnes from area, depth, density, and waste. Liters per Minute Flow Calculator Calculate metric flow rate from a collected volume and elapsed time, with optional cubic-metre-per-hour output. Round Log Weight Calculator Estimate a cylindrical log's volume and mass from diameter, length, wood density, and a moisture allowance. Fence Material Cost Calculator Estimate fence face area, posts, rails, and material cost from dimensions, spacing, and entered unit prices. Fire-Flow Pressure Estimate Estimate a nominal fire-flow rate from a supplied flow coefficient and residual pressure without pretending to perform a code hydraulic design. Wall Stud Framing Calculator Estimate stud count, gross stud length, and plate length for a straight framed wall with optional openings. Minor-Loss K-Factor Calculator Calculate head loss and pressure loss from a fitting K-factor, flow velocity, fluid density, and gravity. Lumber Weight Calculator Estimate the mass of rectangular lumber pieces from dimensions, count, and an entered bulk density. Masonry Mortar Volume Calculator Estimate net mortar volume for a straight masonry wall from wall dimensions, unit dimensions, joint thickness, and waste. Paver Base and Sand Calculator Estimate base aggregate volume, bedding-sand volume, and sand mass for a rectangular paver area. Pipe Weight Calculator Estimate hollow-pipe volume and mass from outside diameter, wall thickness, length, count, and density. Post-Hole Concrete Calculator Estimate concrete volume and order volume for cylindrical post holes from count, diameter, depth, fill fraction, and waste. Sheet-Metal Punching Force Calculator Estimate the force needed to shear a perimeter through sheet material from perimeter, thickness, shear strength, and a safety factor. Rafter Length Calculator Estimate sloping rafter length, roof angle, and total material length from horizontal run, rise, overhang, and count. Rebar Weight and Length Calculator Estimate total reinforcing-bar length, steel volume, and mass from bar diameter, cut length, count, density, and lap allowance. Rivet Shear Diameter Calculator Estimate a circular rivet diameter from design load, rivet count, shear planes, allowable shear stress, and a planning factor. Rolling Pipe Offset Calculator Calculate travel and advance for a two-dimensional rolling pipe offset from offset distance and bend angle. Tapered Retaining-Wall Material Calculator Estimate volume and mass for a straight tapered wall from length, height, top thickness, base thickness, density, and waste. Ramp Slope and Length Calculator Calculate ramp slope as a ratio, percentage, and angle from a measured rise and horizontal run, with the sloped length shown separately. Spindle Speed and Feed Rate Calculator Estimate spindle RPM and a basic milling feed rate from surface speed, tool diameter, flute count, and chip load. Thread Pitch and Lead Calculator Convert threads per inch into inch and millimeter pitch, then calculate lead for single-start or multi-start threads. Parabolic Vertical Curve Calculator Estimate grade change, K value, grade, and elevation at a station on a simple parabolic vertical alignment. Spiral Staircase Geometry Calculator Estimate step count, actual rise, angular tread width, and walking-line arc for a spiral staircase from entered geometry. Vinyl Siding Quantity Calculator Estimate net wall area, order area, and siding panel count from wall dimensions, openings, panel coverage, and waste allowance. Riprap Volume and Mass Calculator Estimate riprap volume, order mass, tonnes, and bag count from a rectangular layer and entered bulk density. Round Pen Area and Panel Calculator Calculate the area and circumference of a circular pen, subtract a gate opening, and estimate whole panel count with an allowance. Metal Roof Area and Cost Calculator Estimate sloped gable-roof surface area, order area, and material-only cost from building dimensions, slope geometry, waste, and a local unit price. Stair Carpet Area and Roll-Length Calculator Estimate carpet surface area and linear roll length for a straight stair run from step count, tread, riser, width, landing, and waste. Cable Sag and Tension Calculator Estimate midspan sag, vertical support reaction, approximate support tension, and support angle for a uniformly loaded cable using a parabolic approximation. Concrete Form Tube Volume Calculator Estimate concrete volume for repeated cylindrical form tubes and convert the order volume into liters and whole bags using an entered bag yield. Thinset Mortar Quantity Calculator Estimate thinset volume, mortar mass, and whole bag count from tiled area, bed thickness, entered dry density, and a transparent allowance. Joint Sealant Cartridge Calculator Estimate sealant volume and whole cartridges from joint length, joint width, joint depth, cartridge volume, and a visible handling allowance. Shiplap Board Quantity Calculator Estimate net wall area, order area, and whole shiplap board count using usable board width, board length, openings, and a waste allowance. Pond Water Volume and Liner Calculator Estimate rectangular pond water volume, liner footprint, and allowance-adjusted liner area from plan dimensions, average depth, and edge overlap. Cylindrical Tank Volume Calculator Calculate full and partially filled cylindrical tank volume from diameter, tank length or height, and a chosen fill percentage. Rectangular Metal Stock Weight Calculator Estimate the mass and tonnes of rectangular metal stock from length, width, thickness, density, and piece count. Milling Material Removal Rate Calculator Calculate milling material removal rate, removed volume over a pass, and idealized cutting time from width, depth, feed rate, and pass length. Taper Angle and Ratio Calculator Calculate diameter change, taper per length, one-in ratio, half-angle, included angle, and slanted edge length from two diameters and a taper length. Fire-Pit Glass Quantity Calculator Estimate the volume, mass, and whole-unit count of fire glass for an annular fire-pit bed from inner and outer diameters, depth, density, and an allowance. Flooring Box Quantity Calculator Estimate net floor area, order area, and whole boxes of flooring from room dimensions, openings, package coverage, and waste. Rectangular Pool Volume and Fill-Cost Calculator Estimate rectangular pool water volume, liters, and a scenario fill cost from length, width, average depth, fill percentage, and entered water price. Round Pool Volume and Fill-Cost Calculator Estimate circular pool water volume, liters, and a scenario fill cost from diameter, average depth, fill percentage, and entered water price. Roof Snow Load Force Calculator Convert an entered snow pressure, roof plan area, and scenario factor into total roof snow force without selecting a jurisdictional design load. Planar True-Position Deviation Calculator Calculate diametral planar true-position deviation from measured X and Y offsets and optionally compare it with an entered tolerance. Wainscoting Panel Quantity Calculator Estimate net wall coverage, panel count, and top-rail length from wall dimensions, openings, panel size, and a cutting allowance. Welding Heat Input Calculator Estimate welding heat input per unit length from current, voltage, travel speed, and an entered efficiency factor. Square Meter Area Converter Convert an area entered in square meters to square feet, square yards, square centimeters, and acres using explicit area factors. Square Yard Area Converter Convert an area entered in square yards to square feet, square meters, square inches, and acres using international-unit relationships. Paver Quantity Calculator Estimate the number of equal-size pavers for a rectangular area using the installed footprint, joint gap, and waste allowance. Plywood Sheet Quantity Calculator Estimate how many rectangular plywood sheets cover a project area, including a selectable cutting and waste allowance. Board Foot Lumber Calculator Calculate board feet, cubic feet, and cubic metres from lumber thickness, width, length, and piece count. Miter Angle Calculator Find the equal miter cut angle for a two-piece joint from the included corner angle, with the complementary saw reference shown separately. Spindle Spacing Calculator Estimate the minimum number of equal spindles needed to keep an entered clear gap at or below its planning limit. Gear Pitch Diameter Calculator Calculate a gear's pitch diameter, circular pitch, module, and angular tooth pitch from tooth count and diametral pitch. Siding Quantity Calculator Estimate net wall area, waste-adjusted siding area, and panel or package count from wall dimensions and product coverage. Wood Beam Span Screening Calculator Screen a simply supported rectangular beam under a uniform load using entered elastic modulus, allowable bending stress, and deflection ratio. Steel Plate Weight Calculator Estimate steel plate volume, mass, and gravitational weight from dimensions, density, and local gravitational acceleration. Wall Surface Area Calculator Find gross wall area, subtract measured door and window openings, and report the usable wall surface for paint, panels, or wall covering. Roof Shingle Bundle Calculator Estimate sloped roof area, 100-area-unit roofing squares, shingle bundles, and individual shingles from plan dimensions and product coverage. Roof Truss Count and Cost Calculator Estimate how many evenly spaced roof trusses span a roof length and calculate a transparent material-plus-installation budget. Square Yards Area and Cost Calculator Convert a rectangular measured area from common length units into square yards and estimate a price per square yard. Tile Quantity and Box Cost Calculator Estimate rectangular tiles, boxes, and material cost from surface dimensions, tile size, grout gap, and a visible waste allowance. Aggregate Tonnage Calculator Estimate aggregate volume, order tonnage, and material cost from a rectangular area, depth, unit weight, and allowance. Wallpaper Roll and Drop Calculator Estimate wallpaper drops and whole rolls from the wall run, ceiling height, roll dimensions, pattern repeat, trimming allowance, and a deliberate spare-roll choice. Privacy Fence Board and Post Planner Plan overlapping privacy-fence boards, sections, posts, rails, and post length from a fence run, gates, overlap, and spacing assumptions. Spaced Wood Fence Materials Calculator Estimate spaced pickets, sections, posts, rails, post length, and covered face area from a wood-fence layout with a visible gap between boards. Vinyl Fence Panel and Post Calculator Estimate vinyl fence panels, posts, caps, and leftover panel coverage from a run, panel length, gate openings, and an explicit allowance. Vinyl Fence Cost Scenario Calculator Estimate vinyl panel, post, gate, and installation scenario costs from a measured run and visitor-supplied prices in any currency. Rectangular Cuboid Mass and Weight Calculator Calculate a rectangular cuboid's volume, mass, gravitational weight, and specific weight from dimensions, density, and gravity. Material Roll Length Calculator Estimate the length of tightly wound sheet, film, tape, paper, or fabric from outer diameter, core diameter, and material thickness. Paint Quantity and Coverage Calculator Estimate paint needed for a measured surface, selected coats, product coverage, waste allowance, and whole container sizes. Junction Box Straight and Angle Pull Sizing Calculator Estimate a planning envelope for horizontal and vertical straight-pull and angle-pull raceway rows using the entered 8× and 6× rules plus other-entry sums. Sod Quantity and Cost Calculator Estimate lawn area, waste-adjusted coverage, sod pieces to order, leftover coverage, and material cost from measured lawn and piece dimensions. Road Base Material Quantity Calculator Estimate compacted volume, order volume, aggregate mass, tonnes, and truckloads for a road or driveway base layer from explicit dimensions and density assumptions. Aquarium Glass Thickness Screening Calculator Estimate a simplified water-panel glass thickness from water depth, plate coefficient, material strength, safety factor, and water properties while keeping the engineering boundary visible.

Recipe Quantity Scaler Scale one ingredient quantity from an original serving count to a new serving count. Alcohol by Volume Calculator Calculate alcohol by volume from pure alcohol volume and total beverage volume. Baker’s Percentage Calculator Express an ingredient mass as a percentage of flour mass for recipe formulation. Coffee-to-Water Ratio Calculator Calculate coffee strength as a water-to-coffee ratio and coffee’s percentage of the combined brew mass. Brine Concentration Calculator Calculate salt concentration by mass from salt and water amounts. Alcohol Dilution Calculator Calculate final mixture volume and added diluent when a stronger beverage is diluted to a target concentration. Cake Serving Calculator Estimate servings from a rectangular cake area and a selected area per serving. Cake Pan Batter Scaling Calculator Scale batter quantity from one round cake pan diameter to another using pan area. Barbecue Food Quantity Calculator Estimate food mass for a barbecue gathering from adult and child guests, portions, and a waste allowance. Bread Spread Quantity Calculator Estimate spread quantity for a number of bread slices with a per-slice amount and an optional allowance. Pizza Area and Topping Calculator Calculate pizza area, area per slice, and topping mass from diameter, slice count, and topping density. Barbecue Grill Area Calculator Estimate minimum cooking-surface area from guest count, area per guest, and a planning allowance. Pancake Recipe Scaling Calculator Scale flour, milk, eggs, and oil amounts from a base serving count to a target number of servings. Homemade Sports Drink Ingredient Calculator Calculate water, sugar, and salt quantities from batch volume and explicit ingredient concentrations. Rice Water Quantity Calculator Calculate water quantity from rice amount and an explicit water-to-rice ratio. Tea Brewing Quantity Calculator Calculate tea leaves and water from serving count and explicit per-serving brewing quantities. Turkey Quantity Calculator Estimate turkey mass from guest count, serving mass per guest, and a planning allowance. Party Drink Volume Calculator Estimate beverage volume and containers from guest count, drinks per guest, serving size, and a planning allowance. DIY Sports Drink Batch Calculator Scale water, sugar, and salt quantities for a visitor-entered homemade sports-drink batch. Bacon Cure Ingredient Scaling Calculator Scale entered salt, sugar, and spice percentages to a selected meat mass for a recipe worksheet. Cooking Volume Measurement Converter Convert common kitchen volume measures between US cups, tablespoons, teaspoons, fluid ounces, milliliters, and liters. Cups to Pounds Ingredient Calculator Estimate an ingredient mass in pounds from cups when you supply that ingredient's grams-per-cup density. Dry to Cooked Pasta Yield Calculator Estimate cooked pasta quantity from dry pasta weight using an adjustable yield factor. Fresh to Dried Herb Conversion Calculator Convert fresh herb volume to a dried-herb estimate with an adjustable strength ratio. Garlic Clove, Gram, and Teaspoon Converter Estimate minced garlic weight and volume from a clove count using explicit per-clove assumptions. Grams to Cups Ingredient Calculator Estimate ingredient volume in cups from grams when you provide grams per cup for that ingredient. Grams to Tablespoons Ingredient Calculator Estimate tablespoons from grams with a user-supplied grams-per-tablespoon density. Grams to Teaspoons Ingredient Calculator Estimate teaspoons from grams with a user-supplied grams-per-teaspoon density. Milliliters to Grams Ingredient Calculator Estimate food mass in grams from milliliters using the ingredient's density in grams per milliliter. Oil to Butter Baking Substitution Calculator Estimate the oil volume used when replacing butter in a recipe with an adjustable butter-to-oil substitution factor. Popcorn Kernel to Popped Volume Calculator Estimate popped popcorn volume and servings from kernel volume using an adjustable expansion factor. Pounds to Cups Ingredient Calculator Estimate ingredient volume in cups from pounds using the ingredient's grams-per-cup density. Salad Calories Scenario Calculator Add ingredient calorie estimates and divide the total across salad servings without assuming a specific food database value. Self-Rising Flour Substitute Calculator Calculate baking powder and salt additions for a specified amount of all-purpose flour. Steak Cooking Time Planning Calculator Estimate a starting cooking time from steak thickness, cooking method, and desired doneness using an adjustable time factor. Turkey Cooking Time Range Calculator Estimate a planning time range from turkey weight and whether the bird is stuffed, then defer to a thermometer and local food-safety guidance. Turkey Defrost Time Calculator Estimate refrigerator or cold-water thawing time from turkey weight and state the cold-water change interval. Uncooked to Cooked Rice Yield Calculator Estimate cooked rice volume and servings from dry rice volume using an adjustable water-absorption yield factor. Fresh, Active-Dry, and Instant Yeast Converter Convert a yeast amount between fresh cake yeast, active dry yeast, and instant yeast using transparent standard ratios. Caffeine Remaining Over Time Calculator Estimate caffeine remaining after a chosen number of hours using an adjustable half-life assumption. Sourdough Hydration Calculator Calculate total flour, total water, dough hydration, and starter contributions for a sourdough formula. Taco Bar Quantity Calculator Estimate tacos, shell packs, filling mass, and combined topping mass for a taco bar from guests, portions, and a visible allowance. Pizza Party Quantity Calculator Estimate planned slices, whole pizzas, served slices, and remaining slices from guests, portions, pizza size by slices, and an extra allowance. Mashed Potato Ingredient Calculator Scale raw potatoes, butter, and milk for a guest count from explicit per-person and per-kilogram recipe ratios. Chilled Drink Ice Calculator Estimate the ice mass needed to cool a water-like drink to a target temperature using an explicit energy-balance model. Priming Sugar Quantity Calculator Estimate a brewing priming-sugar mass from batch volume, target and residual carbonation, and an explicit sugar-yield factor. Ham Quantity per Person Calculator Estimate ham purchase mass from guests, edible serving mass, edible fraction, and a visible leftovers allowance. Beer Pong Supply Planner Plan cups, beverage volume, and replacement balls for a beer-pong session from the number of games and the visible setup assumptions. Wedding Beverage Quantity Planner Estimate alcoholic beverage servings, bottles, and non-alcoholic water servings for an event using explicit guest, duration, and serving assumptions. Ice-Cream Tub Quantity Planner Estimate total ice-cream volume, scoops, and tubs from guests, scoop size, an allowance, and the container size you can buy. Emergency Food Reserve Planner Estimate packaged-food units and total energy for a household reserve from people, days, a chosen daily planning value, and a buffer. Liquid Cooling Time Calculator Estimate a liquid temperature after a time interval, the time to a target temperature, and heat removed using a Newton-cooling model. Salt Dough Recipe Scaling Calculator Scale a craft salt-dough ratio for any flour amount, batch count, and entered salt or water parts while keeping all ingredients in the same measuring unit. Butter Measurement Conversion Calculator Convert butter measured in North American sticks into cups, tablespoons, teaspoons, grams, ounces, and pounds while keeping the regional stick convention visible. Cold Brew Concentrate Ratio Calculator Plan coffee, brew water, concentrate, and dilution water for a cold-brew batch from a finished volume, ratio, and measured yield assumption. Coffee Carbon Footprint Scenario Calculator Estimate a coffee serving or batch footprint from transparent production, transport, packaging, brewing-energy, electricity, and waste factors that you can replace with local data. Pizza Size and Value Comparison Calculator Compare pizza orders by circular area, total price, price per area, and the area advantage of one order over another. Molecular Sulfur Dioxide from pH Calculator Estimate molecular sulfur dioxide from free sulfur dioxide, pH, and an explicit dissociation constant for a simplified acid-equilibrium model. Chocolate Nutrition Scaling Calculator Scale calories, fat, carbohydrate, sugar, and protein from a chocolate nutrition label to a chosen serving count and serving mass. Ham Cooking Time Planning Calculator Estimate a ham cooking-time range from weight and an explicit product-specific time rate, then add a rest period and keep the thermometer check visible. Egg Boiling Time Physics Calculator Estimate egg heating time from mass, starting temperature, water temperature, and a selected center-temperature target. Coffee Caffeine Intake Scenario Calculator Compare planned coffee servings with a visitor-entered daily caffeine limit and a transparent body-weight sensitivity scenario. Coffee Add-On Nutrition Scenario Calculator Estimate caffeine, added sugar, milk, creamer, and total drink calories from a coffee recipe using visitor-supplied label values. Pizza Bake-Time Physics Calculator Estimate pizza bake time from dough thickness, oven temperature, baking surface, and a transparent topping-water allowance. Holiday Meal Calories and Activity Scenario Calculator Add serving calories for a holiday meal, calculate the meal total and per-diner average, and explore an explicit activity-time scenario. Turkey Thawing Time Calculator Estimate refrigerator and cold-water thawing time from turkey weight, with a selected method and food-safety boundaries. Sodium in Salt Calculator Estimate sodium from a salt mass and sodium-chloride purity using reference atomic weights, with outputs for sodium, chloride, and sodium per 100 grams of product. Thanksgiving Meal Planner Estimate turkey weight, kilograms, side-dish servings, and the number of side dishes for a holiday meal with planned leftovers.

Weighted Grade Calculator Combine component percentage scores with relative weights and inspect each contribution to the overall grade. Credit-Weighted 4.0 GPA Calculator Calculate GPA from numeric grade points and matching course credits, with a quality-points breakdown. Required Final Exam Grade Calculator Find the final exam score needed for a target course grade and identify impossible or already-secured targets. Reading Time Calculator Estimate reading duration from a word count and your own reading speed, with a rounded planning allowance. Reading Challenge Pace Calculator Calculate planned pages per day and total planned pages for a reading challenge with an optional buffer. Additive Grade Curve Calculator Apply a clearly stated additive class-average shift to a raw score, with an explicit score cap and both capped and uncapped results. IELTS Overall Band Score Calculator Calculate the overall IELTS band from Listening, Reading, Writing, and Speaking section bands using the official half-band rounding rule. ACT Composite Score Calculator Calculate the current ACT Composite from English, Math, and Reading section scores, with a separate Science and STEM view. Ability Score Point-Buy Planner Plan six ability scores with a transparent 27-point cost table, remaining budget, and derived modifiers. Semester Grade Target Planner Calculate the current weighted contribution, required score on remaining work, and best possible final grade for a semester target.

Uniform Acceleration Motion Find final velocity and displacement from initial velocity, constant acceleration, and time. Newton's Second Law Force Calculate force from mass and acceleration, the core relation of classical dynamics. Kinetic Energy Compute the energy of motion from mass and speed. Gravitational Potential Energy Estimate stored energy from mass, height, and Earth's gravity. Work and Power Find mechanical work from force and distance, and power from work over time. Ohm's Law Solver Solve for voltage, current, or resistance in a simple resistive circuit. Density, Mass, and Volume Solver Solve the density relation for whichever of the three quantities is unknown. Molarity Calculator Find solution concentration from moles of solute and litres of solution. Solution Dilution (M1V1 = M2V2) Find the concentration after diluting a stock solution to a new volume. Ideal Gas Law Solver Solve PV = nRT for pressure, volume, moles, or temperature. pH and Hydrogen Ion Calculator Convert between hydrogen-ion concentration and pH in either direction. Free-Fall Time and Impact Speed Drop time and impact velocity for a height with no air resistance. Linear Momentum Momentum from mass and velocity, with kinetic energy for context. Electric Power (P = VI) Power dissipated from voltage and current. Specific Heat Energy (Q = mcT) Thermal energy to change a mass's temperature. Combined Gas Law Solver Find the missing pressure, volume, or temperature between two gas states. 1:1 Titration Concentration Unknown concentration from a 1:1 mole-ratio titration. Solution Preparation Mass Solute mass needed for a target molarity and volume. Projectile Range (Level Ground) Horizontal range of a launch that lands at launch height, vacuum model. Series and Parallel Resistance Equivalent resistance of a resistor list in series or parallel. Wave Speed, Frequency, and Period Relate wave speed, frequency, wavelength, and period. Reaction Percent Yield Efficiency of a chemical reaction from actual vs theoretical product. Moles and Mass Converter Convert between grams and moles with a user-entered molar mass. pH to pOH and Hydroxide Complete the pH/pOH pair plus hydroxide concentration at 25 C. Hardy-Weinberg Genotype Frequencies Genotype frequencies from one allele frequency under equilibrium. Exponential Population Growth Project a population with constant per-capita growth rate. Percent Error Calculator Compare a measured value with a reference value using absolute, percent, and signed percent error. Ideal Gas Pressure Calculator Calculate ideal-gas pressure from amount, temperature, and volume using consistent SI-compatible inputs. Specific Heat Energy Calculator Calculate thermal energy transferred when a material changes temperature. Wavelength and Frequency Calculator Find wavelength, frequency, period, and angular frequency for a periodic wave. Uniform Acceleration Calculator Calculate acceleration, average velocity, and displacement when initial and final velocity are known. Projectile Motion Calculator Estimate flight time, horizontal range, and maximum height for ideal level-ground projectile motion. Boyle’s Law Calculator Find a gas’s unknown pressure or volume when temperature and amount stay constant. Resistance and Electrical Power Calculator Calculate resistance and power from voltage and current using Ohm’s law. Capacitance and Stored Energy Calculator Calculate capacitance and stored energy from charge and voltage. Reynolds Number Calculator Calculate the dimensionless Reynolds number for a flow from density, speed, length, and dynamic viscosity. Reaction Percent Yield Calculator Compare actual product yield with theoretical yield as a percentage. Air Pressure at Altitude Calculator Estimate pressure at altitude with an isothermal ideal-gas atmosphere model. Acceleration from Force and Mass Calculator Calculate acceleration from a net force and an object’s mass using Newton’s second law. Angle of Repose Calculator Estimate the limiting angle of repose from a static friction coefficient. Angular Displacement Calculator Calculate angular displacement and revolutions from constant angular velocity and elapsed time. Angular Frequency Calculator Convert ordinary frequency into angular frequency and period for a repeating cycle. Ideal Air Density Calculator Estimate ideal dry-air density from absolute pressure and temperature. Exponential Attenuation Calculator Calculate remaining intensity and attenuation in decibels for an exponential-loss model. Bulk Modulus Calculator Calculate a material’s bulk modulus from pressure change and fractional volume change. Absolute Humidity Calculator Calculate absolute humidity from water-vapor mass and the volume of air containing it. Acoustic Impedance Calculator Calculate characteristic acoustic impedance from medium density and sound speed. Ballistic Coefficient Calculator Calculate a simplified ballistic coefficient from mass, drag coefficient, and reference area. Bernoulli Equation Calculator Find downstream pressure from two flow states with a steady incompressible Bernoulli model. Two-Body Calorimetry Calculator Estimate the equilibrium temperature when two bodies with known masses and specific heats exchange heat in an isolated model. Blackbody Radiation Power Calculator Estimate thermal radiation power from area, absolute temperature, and emissivity using the Stefan–Boltzmann model. Bragg’s Law Calculator Calculate diffraction angle or lattice spacing with Bragg’s law for a selected wavelength and order. Boltzmann Factor Calculator Calculate the relative Boltzmann factor for an energy difference at an absolute temperature. Bohr Model Energy and Radius Calculator Estimate a hydrogen-like electron energy level and orbital radius from nuclear charge and principal level. RC Capacitor Charge Time Calculator Calculate the time for a resistor-capacitor circuit to reach a selected percentage of its final charge. Frequency Bandwidth Calculator Calculate bandwidth and center frequency from the lower and upper edges of a frequency band. AC Power and Wattage Calculator Estimate real AC power from voltage, current, power factor, and single- or three-phase selection. Average Impact Force Calculator Estimate average stopping force from vehicle mass, speed, and stopping distance in a simplified energy model. Reflection Angle Calculator Calculate the reflected angle and complementary angle to the surface from an entered angle of incidence. Electric-Field Particle Acceleration Calculator Calculate the acceleration magnitude of a charged particle in a uniform electric field from charge and mass. Coordinated-Turn Bank Angle Calculator Estimate the bank angle for a level coordinated turn from speed, turn radius, and gravitational acceleration. Arrow Speed from Kinetic Energy Calculator Calculate an idealized projectile speed from mass and kinetic energy. Avogadro’s Law Volume Calculator Calculate a new gas volume from an initial volume and the ratio of final to initial amount of gas at constant temperature and pressure. Brinell Hardness Number Calculator Calculate a simplified Brinell hardness number from force, indenter diameter, and indentation diameter. Shaft Angle of Twist Calculator Calculate elastic shaft twist from torque, shaft length, shear modulus, and polar second moment of area. Simply Supported Beam Deflection Calculator Estimate center deflection of a simply supported beam under a center point load using an Euler–Bernoulli elastic model. Average Acceleration Calculator Calculate average acceleration and displacement under constant acceleration from initial velocity, final velocity, and elapsed time. Broad-Crested Weir Flow Calculator Estimate ideal flow over a broad-crested weir from crest width, head, discharge coefficient, and gravity. Altitude Temperature Estimate Estimate temperature at altitude using a supplied sea-level temperature and a linear lapse rate. Simply Supported Beam Reaction Calculator Calculate total load, equal support reactions, and maximum bending moment for a simply supported beam under uniform load. Elevator Apparent Weight Calculator Calculate apparent weight for a person or object in a vertical elevator acceleration scenario. Charles’s Law Gas Volume Calculator Calculate a gas volume after a temperature change at constant pressure using absolute temperatures. Cloud Base Height Estimate Estimate cloud-base height from air temperature, dew point, and a supplied temperature-dew-point lapse approximation. Conductivity to Resistivity Calculator Convert electrical conductivity into resistivity using the reciprocal relation. Compton Wavelength Calculator Calculate a particle’s Compton wavelength from its rest mass using Planck’s constant and the speed of light. Bending Stress Calculator Estimate bending stress from bending moment, distance to the outer fiber, and second moment of area. Centrifugal Force Magnitude Calculator Calculate the frame-dependent outward force magnitude associated with circular motion from mass, speed, and radius. Two-Object Momentum Conservation Calculator Calculate total one-dimensional momentum and the shared velocity after a perfectly inelastic collision. Flow Coefficient of Discharge Calculator Estimate a discharge coefficient from measured flow, opening area, and hydraulic head. Uniform Circular Motion Calculator Calculate tangential speed and centripetal acceleration from radius and period. Brake-Specific Fuel Consumption Calculator Convert a fuel mass flow and delivered engine power into brake-specific fuel consumption. Dripping Faucet Water Loss Calculator Estimate water lost from a dripping faucet over a day or a selected number of days. Household Water Demand Calculator Estimate total household water demand from people, daily per-person use, and a selected number of days. Reusable Bag Break-Even Calculator Compare the purchase cost of reusable bags with disposable-bag cost across a planned number of uses. Cigarette Butt Mass Calculator Estimate the collected mass of cigarette butts from a count and an entered average mass per item. Compost Carbon-Nitrogen Mix Calculator Estimate additional brown material needed to reach a selected brown-to-green mass ratio in a compost mix. Focal Length from Sensor Width and Field of View Calculate approximate focal length from a camera sensor dimension and horizontal field of view. Guitar String Tension Calculator Estimate ideal string tension from unit mass, vibrating length, and target frequency. Ground Sample Distance Calculator Estimate ground sample distance per image pixel from altitude, sensor pixel pitch, and focal length. Hyperfocal Distance Calculator Calculate approximate hyperfocal distance from focal length, f-number, and circle of confusion. Thin-Lens Magnification Calculator Calculate image distance and lateral magnification from focal length and object distance using the thin-lens equation. Source and Load Impedance Matching Calculator Calculate reflection coefficient and voltage transfer for a resistive source and load pair. Ideal Cable Impedance Calculator Calculate ideal characteristic impedance from inductance and capacitance per unit length. Photography Exposure Value Calculator Calculate exposure value at ISO 100 and the adjusted exposure value from f-number, shutter time, and ISO. Rainfall Collection Volume Calculator Estimate rainfall volume collected over an area from rainfall depth and a runoff or collection efficiency. Bleach Solution Dilution Calculator Calculate stock solution volume and added water for a target concentration and final volume. Radioactive Half-Life Age Calculator Estimate elapsed age from a half-life, initial activity or fraction, and remaining activity fraction. Diffusion Coefficient from Displacement Calculator Estimate a diffusion coefficient from root-mean-square displacement, elapsed time, and dimensionality. Electrolysis Mass Calculator Estimate deposited or released mass from current, time, molar mass, electron count, and Faraday's constant. Reversible Entropy Change Calculator Calculate entropy change from reversible heat transfer and absolute temperature. Two-Ion Ionic Strength Calculator Calculate ionic strength for a two-species solution from concentrations and charge numbers. Langmuir Adsorption Isotherm Calculator Calculate adsorbed quantity from maximum capacity, affinity constant, and equilibrium concentration. Chemical Oxygen Demand Concentration Calculator Convert oxygen consumed by a sample into chemical oxygen demand concentration. Angular Velocity from Rotations Calculator Calculate angular velocity and rotations per minute from completed rotations and elapsed time. Archimedes Buoyant Force Calculator Calculate buoyant force and equivalent supported mass from fluid density and displaced volume. Hawking Temperature Estimate Estimate ideal Hawking temperature from a nonrotating black-hole mass. Relative Centrifugal Force Speed Calculator Calculate rotor speed in RPM from relative centrifugal force and rotor radius. Mechanical Energy Calculator Calculate gravitational potential energy, kinetic energy, and their sum from mass, height, and speed. Compressibility and Bulk Modulus Calculator Calculate compressibility and bulk modulus from pressure change, initial volume, and volume change. Fluid Drag Force Calculator Calculate ideal drag force from fluid density, drag coefficient, reference area, and speed. Distance to Horizon Calculator Estimate geometric horizon distance from planetary radius and observer height. Debye Length Calculator Estimate the electrostatic screening length of a dilute electrolyte from temperature, relative permittivity, and ionic strength. Activity Coefficient Calculator Estimate a dimensionless activity coefficient from activity and concentration relative to a one-molar standard state. Calibration Curve Inversion Calculator Convert a measured signal into an estimated quantity using a linear calibration slope and intercept. Cubic Unit Cell Density Calculator Calculate ideal crystal density from unit-cell edge length, atoms per cell, and molar mass. Degree of Unsaturation Calculator Calculate the index of hydrogen deficiency from carbon, hydrogen, nitrogen, and halogen counts. Electron Configuration Calculator Generate a ground-state orbital-filling configuration for an element or ion up to atomic number 118. Pauling Electronegativity Difference Calculator Estimate a bond electronegativity difference from heteronuclear and homonuclear bond energies. Concentration Equilibrium Constant Calculator Calculate a concentration-based equilibrium constant from product and reactant concentrations and stoichiometric coefficients. Gibbs Free Energy Change Calculator Calculate Gibbs free-energy change from enthalpy change, entropy change, and absolute temperature. Michaelis-Menten Rate Calculator Calculate ideal initial enzyme reaction rate from maximum rate, Michaelis constant, and substrate concentration. Mass Concentration to Molarity Calculator Convert a mass concentration and molar mass into molar concentration. Alfvén Velocity Calculator Calculate ideal magnetohydrodynamic Alfvén speed from magnetic field and mass density. Angle of Refraction Calculator Calculate a transmitted ray angle using Snell's law and two refractive indices. Brewster Angle Calculator Calculate the incidence angle for zero reflected p-polarized light at an ideal dielectric interface. Compton Scattering Wavelength Calculator Calculate the ideal Compton wavelength shift and scattered wavelength for a photon angle. Critical Damping Calculator Calculate critical damping, damping ratio, and ideal damping regime for a mass-spring system. Coriolis Acceleration Calculator Estimate horizontal Coriolis acceleration magnitude from speed, latitude, and planetary rotation rate. Cricket Chirp Temperature Estimate Estimate outdoor temperature from cricket chirps per minute using a classic empirical relation. Dry Matter and Water Content Calculator Split a material mass into dry matter and water from a stated dry-matter percentage. Feed Conversion Ratio Calculator Calculate feed conversion ratio from feed consumed and live-mass gain. Fertilizer Application Quantity Calculator Estimate total fertilizer mass and bag count from area, application rate, and package size. Growing Degree Units Calculator Estimate cumulative growing degree units from daily high and low temperatures, a base temperature, and days. Grain Bin Capacity and Mass Calculator Estimate filled cylindrical grain-bin volume and grain mass from dimensions, fill fraction, and bulk density. Bushel to Mass Grain Conversion Calculator Convert a bushel count to estimated mass using an entered commodity-specific mass per bushel. Cat Energy Requirement Estimate Estimate resting and factor-adjusted daily energy from a cat's body mass using a transparent power-law model. Dog Age to Human-Year Estimate Estimate an adult-equivalent human age from dog age using a simple first-year, second-year, and later-year model. Dog Water Intake Planning Estimate Estimate a daily water-planning amount from body mass and a visitor-entered millilitres-per-kilogram rate. Gravitational Acceleration from Mass and Radius Calculator Calculate gravitational acceleration from a spherical body’s mass and radius. Biot Number Calculator Calculate the Biot number from a convection coefficient, characteristic length, and material conductivity. Second-Order Damping Ratio Calculator Calculate natural frequency and damping ratio from mass, damping coefficient, and spring stiffness. Decibel Power Gain Calculator Calculate power gain in decibels from output and input power. Drake Equation Scenario Calculator Multiply supplied astronomical and biological factors into a communicating-civilization scenario estimate. Earth Curvature Drop Approximation Calculator Estimate geometric curvature drop over a supplied surface distance using a spherical Earth approximation. Sensible Enthalpy Change Calculator Calculate a simple enthalpy change from mass, specific heat, and temperature change. Faraday Electrolysis Mass Calculator Estimate deposited mass from current, time, molar mass, electron count, and Faraday’s constant. Gear Ratio and Output Speed Calculator Calculate gear ratio, output speed, and ideal torque multiplication from tooth counts and input speed. Hydraulic Radius Calculator Calculate hydraulic radius from flow cross-sectional area and wetted perimeter. Hydrostatic Pressure Calculator Calculate gauge pressure from fluid density, gravitational acceleration, and depth. Inverse-Square Law Calculator Scale a field or intensity from one distance to another under an inverse-square model. Joule Heating Energy Calculator Calculate resistive heating energy from current, resistance, and time. Knudsen Number Calculator Calculate the ratio of molecular mean free path to a characteristic length. Laser Beam Divergence Calculator Estimate full-angle far-field beam divergence from wavelength and initial beam diameter under a diffraction-limited circular-aperture model. Electric Motor Torque from Power and Speed Calculator Calculate ideal shaft torque from mechanical power and rotational speed. Linear Actuator Force from Pressure Calculator Calculate ideal force from pressure and piston area. Lift Coefficient Calculator Calculate a dimensionless lift coefficient from lift force, fluid density, speed, and reference area. Free-Space Path Loss Calculator Calculate ideal free-space radio path loss from frequency and distance. Ideal Transformer Voltage and Current Calculator Calculate secondary voltage and current from turns ratio and primary values under an ideal transformer model. Buoyant Force and Net Force Calculator Calculate ideal buoyant force and the net vertical force from fluid density, displaced volume, gravity, and object mass. Darcy-Weisbach Head-Loss Calculator Calculate frictional head loss and pressure loss in a pipe from length, diameter, speed, friction factor, density, and gravity. Double-Slit Diffraction Fringe Spacing Calculator Calculate ideal double-slit fringe spacing from wavelength, screen distance, and slit separation. Charge-Carrier Drift Velocity Calculator Calculate charge-carrier drift speed from current, carrier density, carrier charge, and cross-sectional area. Heat-Exchanger Effectiveness from NTU Calculator Calculate counterflow heat-exchanger effectiveness from number of transfer units and heat-capacity ratio. Equivalent Isotropically Radiated Power Calculator Calculate ideal effective isotropic radiated power from transmitter power, antenna gain, and cable loss. Elastic Moduli Relationship Calculator Calculate Young’s modulus and bulk modulus from shear modulus and Poisson’s ratio under isotropic elasticity. Electron Speed from Kinetic Energy Calculator Estimate non-relativistic electron speed from kinetic energy. Axial Elongation Calculator Calculate ideal axial elongation from force, member length, cross-sectional area, and Young’s modulus. Energy-Limited Evaporation Rate Calculator Calculate an ideal evaporation mass rate from supplied heat input and latent heat of vaporization. Diopter and Focal-Length Calculator Convert a positive focal length in millimetres to optical power in diopters and back to metres. Density Altitude Approximation Calculator Estimate density altitude from pressure altitude and outside-air temperature using a standard atmosphere approximation. Differential Pressure Calculator Calculate the signed pressure difference between two supplied pressure readings and its absolute magnitude. Delta-to-Wye Resistor Conversion Calculator Convert three delta-connected resistances into equivalent wye-connected resistances. Electric and Magnetic Field Energy Density Calculator Calculate electric, magnetic, and total field energy density from electric field and magnetic flux density. Excess Electrons from Charge Calculator Calculate the magnitude of excess or missing elementary charges represented by a supplied net charge. Factor of Safety Ratio Calculator Calculate a screening factor-of-safety ratio from an allowable or failure strength and a selected working load. Volumetric Flow Rate from Area and Speed Calculator Calculate volumetric flow rate from a flow cross-sectional area and mean speed. Electrical Mobility Calculator Calculate charge-carrier mobility from drift speed and applied electric field. Full-Wave Bridge Rectifier Output Calculator Estimate peak and average rectified output from AC RMS voltage and two diode drops. Average Force from Impulse Calculator Calculate average force from an impulse and the time interval over which it acts. Projectile Flight Time from Height Calculator Calculate the positive flight time for a projectile launched from a known height with no air resistance. Projectile Maximum Height from Launch Point Calculator Calculate a projectile’s highest vertical position and time to apex from launch conditions. Work from Force, Distance, and Angle Calculator Calculate mechanical work from a constant force, displacement, and included angle. Spring-Mass Oscillation Frequency Calculator Calculate angular frequency, frequency, and period for an ideal mass-spring oscillator. Simple Pendulum Period Calculator Calculate the period and frequency of a small-angle simple pendulum. Centripetal Acceleration Calculator Calculate inward acceleration and angular speed for circular motion from speed and radius. Fluid Continuity Flow Calculator Calculate downstream speed and volumetric flow from two cross-sectional areas and one measured speed. Bernoulli Pressure Change Calculator Calculate downstream ideal-fluid pressure from pressure, speed, height, density, and gravity inputs. Specific Heat from Energy Calculator Calculate specific heat capacity from supplied heat energy, mass, and temperature change. Ideal Gas Density Calculator Calculate ideal-gas density from pressure, molar mass, absolute temperature, and the gas constant. Photon Wavelength from Energy Calculator Calculate photon wavelength from photon energy using Planck’s constant and the speed of light. Optical Lens Power Calculator Calculate optical power in diopters from a thin-lens focal length. Work from Kinetic Energy Change Calculator Calculate net work from mass and initial and final speeds using the work-energy theorem. Thermal Efficiency from Work and Heat Calculator Calculate thermal efficiency and rejected heat from useful work and input heat. Thermal Conduction Resistance Calculator Calculate planar thermal resistance and steady heat-transfer rate through a material slab. Thermal Radiation Power Calculator Calculate idealized radiative power from emissivity, area, and absolute temperature. Electric Field from a Point Charge Calculator Calculate electric-field magnitude and potential from a point charge and distance. Snell’s Law Refraction Angle Calculator Calculate a refracted angle from two refractive indices and an incident angle. Critical Angle Calculator Calculate the critical angle for total internal reflection from a higher-index medium to a lower-index medium. Cube Density from Mass and Side Calculator Calculate the density of a cube from its mass and side length, with the cube volume shown for checking. Darcy’s Law Flow Rate Calculator Estimate porous-medium flow rate from permeability, area, pressure difference, viscosity, and flow length. Darcy Friction Factor from Head Loss Calculator Rearrange the Darcy–Weisbach relation to estimate a dimensionless friction factor from measured head loss and pipe conditions. Froude Number Calculator Calculate the Froude number for a flow or moving body from speed, characteristic length, and gravity. Heat Capacity from Energy and Temperature Change Calculator Calculate the heat capacity of a body from energy transferred and the resulting temperature change. Heat Transfer Coefficient Calculator Estimate a convective heat-transfer coefficient from heat rate, area, and temperature difference. Hydraulic Gradient Calculator Calculate hydraulic gradient from head loss and the flow distance between two points. Lorentz Force Component Calculator Calculate electric and magnetic force components on a moving charge under a stated same-direction component convention. Force Between Parallel Current-Carrying Wires Calculator Calculate the ideal magnetic force between two long parallel current-carrying wires. Mach Number Calculator Calculate Mach number from an object's speed and the local speed of sound. Mechanical Advantage Calculator Calculate ideal mechanical advantage from load force and applied effort force. Newton’s Law of Cooling Calculator Estimate an object's temperature after a time interval using a first-order Newton cooling model. Nusselt Number Calculator Calculate the dimensionless Nusselt number from a heat-transfer coefficient, characteristic length, and thermal conductivity. Physical Pendulum Period Calculator Calculate the small-angle period and frequency of a rigid-body physical pendulum from inertia, mass, pivot distance, and gravity. Pipe Velocity from Flow Rate and Diameter Calculator Calculate mean pipe velocity from volumetric flow rate and circular pipe diameter. Prandtl Number Calculator Calculate the Prandtl number from specific heat, dynamic viscosity, and thermal conductivity. Lensmaker’s Equation Calculator Calculate thin-lens focal length and optical power from refractive indices and the two surface radii. Enzyme Activity from Product Formation Calculator Calculate enzyme activity from the amount of product formed, reaction time, and sample volume. Electrochemical Cell EMF Calculator Calculate the ideal cell electromotive force from cathode and anode reduction potentials. Graham's Law of Effusion Calculator Compare gas effusion or diffusion rates from the molar masses of two gases. Heat of Combustion per Mass Calculator Calculate the energy released per unit mass from a combustion measurement. Isoelectric Point from Adjacent pKa Values Calculator Estimate the isoelectric point from the two pKa values that bracket the neutral zwitterion. Kp from Kc Equilibrium Constant Calculator Convert a concentration-based equilibrium constant to a pressure-based constant for a gas reaction. Born-Landé Lattice Energy Calculator Estimate ionic lattice energy per mole from charges, interionic distance, Madelung constant, and Born exponent. Atmospheric Water-Vapor Mixing Ratio Calculator Calculate the water-vapor mixing ratio from vapor pressure and total atmospheric pressure. Miller Indices from Lattice Intercepts Calculator Convert integer lattice intercepts into the smallest whole-number Miller indices for a crystal plane. Nernst Equation Cell Potential Calculator Calculate nonstandard electrochemical potential from standard potential, temperature, electron count, and reaction quotient. Normality from Molarity Calculator Calculate solution normality and total equivalents from molarity, reaction-equivalent factor, and volume. Osmotic Pressure Calculator Calculate ideal osmotic pressure from solute molarity, van't Hoff factor, and temperature. Percent Ionic Character Calculator Estimate percent ionic character from the electronegativity difference using the Pauling relationship. Gibbs Phase Rule Degrees of Freedom Calculator Calculate degrees of freedom from the number of components, phases, and externally fixed intensive variables. pKa from Ka Calculator Convert an acid dissociation constant into pKa using the base-10 logarithm. Temperature Coefficient Q10 Calculator Calculate the Q10 temperature coefficient from two rates measured at two temperatures. Reaction Quotient from Activities Calculator Calculate a simple reaction quotient from product and reactant activities with explicit stoichiometric exponents. Saponification Value Calculator Calculate milligrams of potassium hydroxide required per gram of oil or fat from a blank and sample titration. Water Hardness as CaCO3 Calculator Convert dissolved calcium and magnesium concentrations into equivalent water hardness as calcium carbonate. Young-Laplace Pressure Calculator Calculate ideal gauge pressure across a spherical liquid interface from surface tension and radius. Moment of Inertia Shape Calculator Calculate mass moment of inertia for common uniform rods, disks, hoops, and rectangular plates about a stated central or end axis. Three-Phase Motor Current Calculator Estimate the line current required by a balanced three-phase motor from output power, voltage, power factor, and efficiency. Sheet-Metal Bend Allowance Calculator Estimate bend allowance and flat-pattern length from bend angle, inside radius, thickness, K-factor, and straight legs. Brake Mean Effective Pressure Calculator Calculate brake mean effective pressure from engine torque, displacement, and two- or four-stroke cycle selection. Engine Airflow CFM Calculator Estimate theoretical engine airflow from displacement, engine speed, volumetric efficiency, and engine cycle. Vertex Distance Power Conversion Calculator Convert an optical power between two vertex planes using the thin-lens vertex-distance relation. Schwarzschild Radius Calculator Calculate the ideal event-horizon radius of a nonrotating, uncharged black hole from its mass. Molar Curie Constant Calculator Estimate the SI molar Curie constant from an effective magnetic moment expressed in Bohr magnetons. Curie-Law Magnetic Susceptibility Calculator Calculate ideal molar magnetic susceptibility from a Curie constant and absolute temperature. Daylight Hours by Latitude Calculator Estimate daylight duration from latitude, day of year, and axial tilt using a simple solar-declination model. Gear Diametral Pitch Calculator Calculate diametral pitch, circular pitch, and metric module from gear teeth and pitch diameter. Flywheel Energy Storage Calculator Estimate usable rotational energy between maximum and minimum flywheel speeds from moment of inertia. Geometric Propeller Pitch Calculator Estimate theoretical propeller pitch from blade angle and the reference radius of the blade section. Four-Wheel-Drive Crawl Ratio Calculator Calculate total low-range crawl ratio from first gear, transfer-case reduction, and final-drive ratio. Barn and Pole Relativity Calculator Explore Lorentz contraction and the relativity-of-simultaneity gap in a pole-and-barn thought experiment. Ideal Electric Dipole Field Calculator Estimate the far-field magnitude and potential of an ideal electric dipole on its axial or equatorial line. Exoplanet Transit Depth Calculator Estimate the fractional and percentage drop in starlight when a planet crosses its star in a central transit. Fresnel Zone Radius Calculator Calculate a radio-link Fresnel-zone radius and diameter at a point between two antennas. Fermi–Dirac Occupation Calculator Estimate the equilibrium occupation probability of an energy state from its energy, Fermi level, and temperature. Hall Coefficient Calculator Calculate Hall coefficient and a one-carrier density estimate from Hall voltage, sample thickness, current, and magnetic field. Harmonic Wave Equation Calculator Evaluate displacement, wave speed, angular frequency, and wave number for a sinusoidal traveling wave. Helical Coil Geometry Calculator Estimate axial length and wire path length for a regular helical coil from diameter, turn count, and pitch. Helmholtz Resonator Frequency Calculator Estimate the resonance frequency of a bottle-like Helmholtz resonator from opening area, cavity volume, neck geometry, and sound speed. RC High-Pass Filter Calculator Calculate cutoff frequency, magnitude gain, gain in decibels, and phase for an ideal first-order RC high-pass filter. Hohmann Transfer Calculator Estimate the two ideal impulse burns and transfer time between two coplanar circular orbits around the same central body. Hubble's Law Calculator Estimate a distant galaxy's recession velocity from distance and an entered Hubble constant. Hydraulic Conductivity Calculator Estimate Darcy discharge from hydraulic conductivity, cross-sectional area, head difference, and flow length. Hydraulic Jump Calculator Estimate sequent depth, depth ratio, and idealized energy loss for a rectangular-channel hydraulic jump. Log Mean Temperature Difference Calculator Calculate the logarithmic mean temperature difference between two streams in a counterflow or parallel-flow heat-exchanger setup. Orifice Flow Rate Calculator Estimate volumetric flow through a sharp-edged orifice from discharge coefficient, area, pressure difference, and fluid density. Poiseuille Flow Calculator Calculate ideal laminar flow through a circular tube from pressure drop, radius, length, and dynamic viscosity. Stokes' Law Drag Calculator Estimate the low-speed viscous drag on a small spherical particle moving through a fluid. Mean Free Path Calculator Estimate the mean distance and mean time between molecular collisions in a dilute ideal gas. Optical Density Calculator Calculate optical density, transmission, and attenuation from incident and transmitted light intensity. Radiation Pressure Calculator Calculate ideal light pressure and force for a perfectly absorbing or perfectly reflecting surface. Net Positive Suction Head Calculator Calculate available net positive suction head from pump suction pressure, fluid vapor pressure, density, and gravity. Pneumatic Cylinder Force Calculator Estimate ideal and efficiency-adjusted push force from air pressure and piston bore diameter. Rocket Specific Impulse Calculator Calculate specific impulse and equivalent exhaust velocity from rocket thrust and propellant mass-flow rate. Atom and Ion Composition Calculator Calculate mass number, neutron count, and electron count from proton count, neutron count, and ionic charge. Boiling Point from Vapor Pressure Calculator Estimate a liquid's boiling temperature at a target pressure with a two-point Clausius–Clapeyron model. Boiling Point at Altitude Calculator Estimate standard-atmosphere pressure and water-like boiling temperature at altitude using a barometric and Clausius–Clapeyron approximation. Chemical Equation Balancer Balance a chemical equation by conserving the elements in the entered reactant and product formulas. Combustion Analysis Empirical Formula Calculator Estimate an empirical formula from measured masses of carbon, hydrogen, oxygen, and nitrogen in a sample. Hydrocarbon Combustion Stoichiometry Calculator Calculate ideal oxygen, carbon-dioxide, and water amounts for complete combustion of a hydrocarbon CxHy. Crude Protein from Nitrogen Calculator Estimate crude protein mass and percentage from measured nitrogen and an entered nitrogen-to-protein factor. Tank Detention Time Calculator Calculate theoretical detention time from effective tank volume and flow rate, with hours and days shown separately. Effective Nuclear Charge Calculator Estimate effective nuclear charge with a transparent, simplified Slater-rule screening scenario. Molar Ratio from Masses Calculator Convert two chemical masses to moles and compare their amount ratio using entered molar masses. Acid–Base Neutralization Volume Calculator Estimate the volume of one acid or base solution required to neutralize another from concentration, volume, and equivalent stoichiometry. Integrated Rate Constant Calculator Calculate a zero-, first-, or second-order rate constant from initial concentration, final concentration, and elapsed time. Serial Dilution Calculator Calculate the final concentration and cumulative dilution from a repeated per-step retained fraction. Total Dissolved Solids Estimate Estimate total dissolved solids from specific conductance with an entered conversion factor and optional local intercept. Vapor Pressure from Temperature Calculator Estimate vapor pressure at a target temperature from a reference pressure and enthalpy of vaporization using Clausius–Clapeyron. First-Order Crossover Frequency Calculator Estimate the transition frequency and time constant of an ideal first-order RC crossover network. Valve Flow Coefficient (Cv) Calculator Estimate liquid flow from a valve flow coefficient, pressure drop, and specific gravity. Sound Level Distance Attenuation Calculator Estimate free-field sound-level change when the distance from a point source changes. Piston Engine Displacement Calculator Calculate swept engine displacement from cylinder bore, stroke, and cylinder count. Friction Coefficient from Force Calculator Estimate a static or kinetic friction coefficient from friction force and normal force. Gay-Lussac Pressure–Temperature Law Calculator Estimate a gas pressure after a temperature change at constant volume and fixed amount of gas. Magnetic Permeability Calculator Calculate absolute and relative magnetic permeability from magnetic flux density and magnetic field strength. Mass–Spring Natural Frequency Calculator Calculate angular frequency, frequency, and period for an ideal undamped mass–spring oscillator. AC Power Factor Calculator Calculate apparent power, power factor, reactive power, and phase angle from real power and RMS voltage/current. Four-Band Resistor Color Code Calculator Decode the nominal resistance and tolerance range of a standard four-band resistor. Resistor Johnson Noise Calculator Estimate ideal Johnson–Nyquist voltage and current noise for a resistor over a selected bandwidth. Sabine Reverberation Time Calculator Estimate room reverberation time from room volume and total equivalent absorption area. Relative Humidity from Dew Point Calculator Estimate relative humidity and vapor-pressure deficit from air temperature and dew-point temperature. Piston Force from Pressure Calculator Calculate ideal force on a circular piston from net pressure and piston diameter. Mean Piston Speed Calculator Calculate mean piston speed from engine stroke and rotational speed. API Gravity and Specific Gravity Calculator Convert petroleum specific gravity at 60 °F into API gravity, or reverse the relation for a transparent planning check. Exhaust Pipe Diameter from Flow Rate Calculator Estimate the circular flow area and internal diameter needed for a chosen volumetric flow and target average gas velocity. Lifetime-Limited Laser Linewidth Calculator Estimate the Fourier-limited linewidth associated with a finite excited-state lifetime and show the corresponding coherence-time scale. Diffraction-Limited Laser Spot Size Calculator Estimate the Airy-disk diameter, radius, and area for a circular aperture or focused beam using wavelength and focal geometry. Magnetic Dipole Moment Calculator Calculate the ideal magnetic dipole moment of a multi-turn current loop from turns, current, and loop area. Magnus-Style Lift Force Calculator Estimate a transverse aerodynamic force using density, speed, reference area, and a supplied lift coefficient for a spinning or curved-flow object. Spherical Mirror Equation Calculator Find image distance, magnification, and mirror curvature from focal length and object distance using the signed mirror convention. Particle Number Density Calculator Calculate the number of particles per volume and the volume represented by a supplied particle count. Porosity and Kozeny–Carman Permeability Estimate Calculate void fraction and an idealized intrinsic permeability estimate from porosity, grain diameter, and a supplied Kozeny constant. Power-to-Weight Ratio Calculator Compare a machine or vehicle's power with its mass in W/kg, kW per metric tonne, and horsepower per metric tonne. Principal Stress and Maximum Shear Calculator Resolve a two-dimensional stress state into principal stresses, maximum in-plane shear stress, and principal-angle orientation. Pulley Mechanical Advantage Calculator Estimate ideal and efficiency-adjusted effort, mechanical advantage, and rope travel for a block-and-tackle style pulley arrangement. Two-Body Recoil Energy Calculator Estimate recoil velocity and kinetic energy from an ideal isolated two-body momentum exchange. Two-Force Resultant Calculator Add two planar force vectors by magnitude and angle, returning Cartesian components, resultant magnitude, and direction. Root-Mean-Square Molecular Speed Calculator Calculate the ideal-gas root-mean-square molecular speed from temperature and molar mass. Signal-to-Noise Ratio Calculator Convert signal and noise power into a linear ratio, decibel value, and percentage noise relative to the signal. Simple Harmonic Motion Position Calculator Evaluate displacement, velocity, and acceleration at a time in ideal sinusoidal motion from amplitude, frequency, and phase. Electromagnetic Skin Depth Calculator Estimate the depth at which a sinusoidal electromagnetic field falls to 1/e in a conductor from frequency, permeability, and conductivity. Sound Absorption Coefficient Calculator Calculate the absorbed energy and normal-incidence absorption coefficient from incident and reflected sound energy. Quadratic-Drag Terminal Velocity Calculator Estimate terminal speed when gravitational force balances quadratic drag in a fluid. Latitude and Longitude Distance Calculator Estimate great-circle distance and initial bearing between two geographic coordinates using a transparent spherical Earth model. Mass Percent of a Solution Calculator Calculate the mass percentage of a solute in a solution and show the corresponding mass fraction and parts-per-million estimate. Molar Mass from Gas Measurements Calculator Estimate a gas sample's molar mass from measured mass, pressure, volume, and absolute temperature using the ideal-gas relation. Protein Solubility Assay Calculator Convert dissolved protein mass and sample volume into soluble concentration, recovery percentage, and undissolved remainder for a transparent assay summary. Radioactive Activity after Half-Lives Calculator Estimate remaining activity, undecayed fraction, decay constant, and activity lost after a chosen elapsed time and half-life. Pellet Resuspension Concentration Planner Estimate final cell concentration and the buffer volume needed to resuspend a pellet to a selected target concentration. Stoichiometric Theoretical Yield Calculator Calculate product moles and mass from a limiting-reactant amount, balanced-equation coefficients, and product molar mass. General Stoichiometric Titration Calculator Calculate an analyte concentration from titrant concentration, measured volumes, and balanced-reaction coefficients beyond the simple 1:1 case. Two-Photon Absorption Rate Calculator Estimate weak-field two-photon absorption events from a cross section, photon flux, and number of absorbing molecules. Water Saturation Vapor Pressure Calculator Estimate saturation vapor pressure over liquid water or ice from temperature using a pressure-adjusted Buck formulation and show the result in common pressure units. Thin-Film Interference Calculator Estimate the optical path difference and nearest constructive or destructive reflection condition for a uniform thin film. Afocal Laser Beam Expander Calculator Calculate ideal beam diameter, angular-divergence ratio, and afocal magnification from two lens focal lengths. Manometer Pressure Difference Calculator Calculate gauge and absolute pressure from a manometer liquid density, column-height difference, gravity, and atmospheric pressure. Two-Body Reduced Mass Calculator Calculate the reduced mass and relative-motion kinetic energy of a two-body system from two masses and their relative speed. Elastic Section Modulus Calculator Calculate second moment of area, elastic section modulus, and simple elastic bending stress for common symmetric cross-sections. Synodic Period Calculator Calculate the time for two orbiting bodies to return to the same relative angular configuration from their orbital periods. Thermal Diffusivity Calculator Calculate thermal diffusivity from thermal conductivity, density, and specific heat capacity. Aircraft Wing Loading Calculator Calculate aircraft wing loading from mass, gravity, and projected wing planform area, with optional customary-unit output. Shear Strain and Stress Calculator Calculate engineering shear strain, angular distortion, and elastic shear stress from lateral displacement, layer height, and shear modulus. Von Mises Stress Calculator Calculate equivalent von Mises stress, yield utilization, and remaining stress margin from three principal stresses. Gauss's Law Flux Calculator Calculate electric flux, enclosed charge, and the ideal spherical-surface electric field using Gauss's law. J-Pole Antenna Dimension Calculator Estimate the wavelength, half-wave radiating section, quarter-wave matching section, and total 3/4-wave J-pole length from frequency. Lumen and Illuminance Calculator Calculate luminous flux from candela and solid angle, then estimate illuminance in lux and foot-candles over an area. Lux to Foot-Candle Converter Convert an illuminance value between lux and foot-candles using the NIST conversion factor. Minute of Angle Target-Size Calculator Convert a minute-of-angle value and viewing distance into the corresponding linear size and angular size in radians. AM Modulation Index Calculator Calculate amplitude-modulation depth, envelope limits, sideband amplitudes, and ideal single-tone AM power ratios. NE555 Astable Frequency Calculator Estimate the oscillation frequency, period, timing intervals, and duty cycle of a standard NE555 astable circuit. Redshift and Blueshift Calculator Calculate spectral redshift or blueshift from rest and observed wavelengths, with a low-redshift velocity approximation and scale factor. Rydberg Equation Calculator Calculate a hydrogen-like spectral transition wavelength, wavenumber, and photon energy from atomic number and energy levels. Solenoid Magnetic Field Calculator Estimate the internal magnetic field, magnetic field strength, and turns-per-length of an ideal long solenoid. Cell and Solution Dilution Calculator Use C₁V₁ = C₂V₂ to find the stock volume, diluent volume, and dilution factor for a target concentration and final volume. CO₂ Grow Room Gas Requirement Calculator Estimate the theoretical CO₂ gas volume, amount, and mass needed to raise a sealed room from one measured ppm level to another at entered temperature and pressure. Grass Seed Quantity Calculator Estimate the base and purchase quantity of grass seed from a rectangular area, a label seeding rate, and an optional allowance for uneven establishment. Mulch Volume and Bag Calculator Calculate mulch volume from a rectangular area and layer depth, then estimate the liters and bags needed after an explicit waste allowance. Plant Population and Row Spacing Calculator Estimate how many planting rows, plants per row, and total planting positions fit inside a rectangular bed using center-to-center spacing. Potting Soil Volume and Bag Calculator Estimate the fill volume for repeated rectangular containers, apply a fill percentage, and round the result to whole bags. Raised Bed Soil Volume Calculator Calculate the soil volume for a rectangular raised bed and estimate bag count after a chosen settling or top-up allowance. Tree Spacing and Hectare Density Calculator Estimate theoretical tree density from row and in-row spacing and scale it to a selected land area without treating the result as a stocking prescription. Vegetable Row Seed Quantity Calculator Estimate seed positions, adjusted seed count, and seed mass for a row using spacing, germination, establishment, and seeds-per-gram inputs. Water-Soluble Fertilizer Mass from ppm Calculator Convert a chosen nutrient target in ppm and solution volume into nutrient mass, product mass from a label percentage, and whole packets. Isotope-Weighted Atomic Mass Calculate an element's average atomic mass from isotope masses and their percentage abundances. Particles, Moles, and Mass Bridge Convert a particle count or mole amount into the corresponding moles, particles, and mass for a supplied molar mass. Mass and Molar Concentration Calculate mass concentration and molar concentration from solute mass, final solution volume, and molar mass. Double Bond Equivalent Calculator Estimate degrees of unsaturation from carbon, hydrogen, nitrogen, and halogen counts in an organic formula. Solution Dilution Factor Calculate how many times a stock solution must be diluted to reach a target concentration and show the final-to-stock fraction. Henderson-Hasselbalch Buffer Calculator Estimate buffer pH from pKa and the conjugate-base-to-acid concentration ratio. Hydrogen-Ion Concentration and pH Convert between pH and hydrogen-ion concentration while showing pOH under the 25 °C dilute-aqueous convention. Precipitation Net-Ionic Equation Builder Build a bounded precipitation net-ionic equation from selected aqueous ions and a supported insoluble product pair. Percent w/v to Molarity Converter Convert grams-per-100-milliliters percentage concentration into molarity using the solute molar mass. Common Chemical Formula Name Lookup Look up the common name and formula class for a bounded set of frequently encountered chemical formulas. Parallel-Plate Capacitance and Stored Energy Estimate the capacitance, charge, stored energy, and electric field of an ideal parallel-plate capacitor. Quadratic Drag Force and Terminal Speed Calculate idealized quadratic drag force and the corresponding terminal speed for an object moving through a fluid. Poisson's Ratio from Axial and Lateral Strain Calculate Poisson's ratio and the dimensional changes of a specimen from signed axial and lateral strains. Mass Moment of Inertia for Common Shapes Calculate the mass moment of inertia about a stated idealized axis for a point mass, rod, hoop, disk, sphere, or cylinder. Normal Force on a Supported Incline Estimate the contact normal force for a mass on an incline with an optional force directed away from or toward the surface. Circular Orbital Period Calculate the period, circular speed, and local gravitational acceleration for an ideal circular orbit around a central mass. Laminar Pipe Flow by Hagen–Poiseuille Estimate flow rate, mean speed, and Reynolds number for a pressure-driven Newtonian fluid in a circular pipe. One-Dimensional Impulse and Momentum Calculate initial and final momentum, impulse, average force, and kinetic-energy change from a one-dimensional velocity change. Drake Equation Civilization Estimate Estimate the number of detectable technological civilizations from the seven factors in the Drake equation. Binoculars Angular-Size Range Estimate the distance to a target of known height from its apparent angular size and binocular magnification. Vehicle Center of Mass from Axle Loads Estimate a vehicle's longitudinal center of mass from front and rear axle loads and wheelbase. Elevated Vehicle Jump Distance Estimate flight time, horizontal distance, and impact speed for an ideal projectile launched from an elevated ramp. Ideal Constant-Acceleration Interstellar Travel Estimate one-way travel time for a symmetric accelerate–cruise–decelerate journey to a stated distance. Light Frequency from Wavelength Calculate electromagnetic-wave frequency, period, photon energy, and wavenumber from wavelength in vacuum. Fulcrum Lever Balance Find the effort force, mechanical advantage, and ideal pivot reaction for a two-force lever in static balance. Schwarzschild Gravitational Time Dilation Estimate the proper time elapsed near a spherical nonrotating mass compared with a distant coordinate-time interval. Hair-Width Diffraction Estimate Estimate the first diffraction minimum angle and screen displacement for light diffracted by an opaque hair-sized obstacle. Hydrogen-Like Atom Energy Transition Calculate Bohr-model energy levels, orbit radii, and photon wavelength for a one-electron ion transition. Lightning Distance from Thunder Delay Estimate how far away a lightning flash was from the time between seeing the flash and hearing thunder. Radar Horizon Range Estimate the geometric line-of-sight range to a target from radar antenna height, target height, and an effective Earth radius. Luminosity from Flux and Distance Calculate a source's total radiated power from measured energy flux and distance using the inverse-square relationship. Quantum Number Validity and Orbital Capacity Check a set of electron quantum numbers and calculate its shell, subshell, orbital, and electron capacities. Poise and Stokes Viscosity Converter Convert dynamic viscosity to SI and poise units and derive kinematic viscosity in stokes from density. 3D Acceleration Magnitude Find the total acceleration magnitude and g-equivalent from perpendicular x, y, and z acceleration components. Aircraft Ground Speed with Wind Vector Calculate an aircraft's ground speed and track from airspeed, heading, and meteorological wind direction and speed. Foot-Pounds of Work and Energy Calculate mechanical work in foot-pounds-force from a force, distance, and included angle, then convert it to joules. Laser Beam Irradiance Estimate optical power density from laser power and circular spot diameter, with watts per square metre and decibel output. Coefficient of Performance Calculate a heating or cooling system's coefficient of performance from useful output energy and supplied input energy. Cube-Root Blast-Scaling Radius Scale a reference blast-effect radius to a different TNT-equivalent yield with the cube-root scaling relationship. Capacitive Transformerless Supply Sizing Estimate capacitive reactance, reactive VA, and series-capacitor value for a target RMS current at a stated AC voltage and frequency. Mass from Density and Volume Calculate an object's mass from its density and volume while returning the SI volume and specific-volume equivalents. Free Fall with Quadratic Air Resistance Estimate fall time, final speed, and terminal speed for an object dropped from rest under a constant quadratic-drag model. Root-Mean-Square Molecular Speed Calculate the root-mean-square speed of ideal-gas molecules from temperature and molar mass. Sound Wavelength from Speed and Frequency Calculate a sound wave's wavelength and period from its propagation speed and frequency. Surface Tension from Force and Length Calculate surface tension from a measured force acting along a liquid-surface length. van der Waals Gas Pressure Calculate non-ideal gas pressure from amount, temperature, volume, and van der Waals constants. Vickers Hardness Number Calculate Vickers hardness from indentation load and the two measured diagonals of a square-pyramidal diamond impression. Energy to TNT Equivalent Convert an energy value in joules to an equivalent mass of TNT using the standard energy-equivalence factor. Specific Gas Constant Calculate a gas's specific gas constant from its molar mass using the universal molar gas constant. Wavenumber from Wavelength Calculate spatial wavenumber, cycles per metre, and frequency from wavelength and propagation speed. Wind Correction Angle Solve the horizontal wind triangle for a heading correction, groundspeed, and crosswind components along a chosen course. Wheatstone Bridge Balance Calculate the unknown resistance at balance and the detector voltage for a four-resistor Wheatstone bridge. Apparent Power in kVA Calculate single-phase or balanced three-phase apparent power, real power, and reactive power from RMS voltage, current, and power factor. Voltage Regulation Calculate voltage regulation from no-load and full-load output voltage and show the resulting load drop. Young's Modulus from Stress and Strain Calculate tensile or compressive Young's modulus from force, cross-sectional area, original length, and extension. RMS Voltage for a Sine Wave Convert sinusoidal peak voltage to RMS, peak-to-peak, average-rectified voltage, and resistive-load power. Water Pressure at Depth Calculate gauge and absolute hydrostatic pressure below a fluid surface from depth, density, surface pressure, and gravity. Telescope Field of View Estimate telescope magnification, true angular field of view, and exit pupil from telescope and eyepiece specifications. Horsepower to Amps Estimate motor input current from mechanical horsepower, voltage, phase, power factor, and efficiency. Open-Channel Flow (Manning Equation) Estimate uniform flow velocity and discharge in a rectangular open channel from geometry, slope, and Manning roughness. Speed of Sound in a Solid Estimate longitudinal sound speed in a solid from Young's modulus and density, then calculate travel time over a path. Solar Elevation and Azimuth Angle Calculate the Sun's elevation, zenith, and compass azimuth from latitude, solar declination, and hour angle. Sunrise and Sunset from Solar Geometry Estimate sunrise, sunset, daylight duration, and solar noon from latitude, declination, longitude, time zone, and equation of time. True Airspeed from Equivalent Airspeed Estimate true airspeed from equivalent airspeed and actual air density using the density-ratio relationship. Water Dynamic Viscosity by Temperature Estimate liquid-water dynamic viscosity from temperature using a compact atmospheric-pressure correlation. Watt-Hours from Power and Time Calculate energy use in watt-hours, kilowatt-hours, and joules from power, runtime, quantity, and efficiency. Wave Velocity from Wavelength and Frequency Calculate wave speed, period, and angular frequency from wavelength and ordinary frequency. Wet-Bulb Temperature Estimate wet-bulb temperature from air temperature and relative humidity with the published Stull approximation. Vertical Exaggeration Calculate the vertical exaggeration of a profile from its horizontal and vertical map scales. Microbial Log Reduction Convert initial and surviving organism counts into log reduction, remaining fraction, and percent reduction. qPCR Amplification Efficiency Convert the slope of a qPCR standard curve into amplification efficiency and fold amplification per cycle. Mutation Frequency from Counts Calculate the observed fraction of mutant cells or organisms and express it as a percent or per-million frequency. Plant Water Potential Estimate solute potential from molarity, van't Hoff factor, and temperature, then combine solute, pressure, and gravitational terms. Tree Height from Clinometer Angles Estimate tree height from horizontal distance, top and base sight angles, and observer eye height. Wire Resistance from Resistivity Calculator Calculate the resistance of a uniform conductor from material resistivity, length, and cross-sectional area. VSWR and Return Loss Calculator Convert a reflection-coefficient magnitude into voltage standing-wave ratio, return loss, and reflected power. Stopping Distance Calculator Estimate reaction distance, braking distance, and total stopping distance from speed, reaction time, and deceleration. Inclined-Plane Force Calculator Estimate normal force, downhill gravity, kinetic friction, and the force needed to move an object up an incline at constant speed. LED Series Resistor Calculator Choose a current-limiting resistor for one or more LEDs in series and estimate the resistor voltage and power. Darcy–Weisbach Pipe Friction Loss Calculator Estimate pipe friction head loss and pressure loss from the Darcy friction factor, length, diameter, velocity, and fluid density. Air Kinematic Viscosity Calculator Calculate air kinematic viscosity from dynamic viscosity and density, with a convenient centistokes conversion. Polar Moment of Area Calculator Find the polar second moment of area for a solid circular shaft or an annular tube and show its torsional section modulus. Pump Horsepower Calculator Estimate hydraulic and brake horsepower from pump flow, head, specific gravity, and pump efficiency. Resultant Velocity Calculator Combine perpendicular velocity components to find resultant speed, horizontal direction, and elevation angle. Ripple Capacitor Size Calculator Estimate the minimum bulk capacitance needed for a switching-converter ripple limit while exposing the ESR contribution. Ideal Flyback Converter Calculator Estimate flyback output voltage and the duty cycle needed for a target from input voltage, turns ratio, and diode drop. Ideal Forward Converter Calculator Estimate forward-converter output voltage and target duty cycle from input voltage, transformer turns ratio, and diode drop. Decibel Ratio Calculator Convert a positive measured-to-reference power or amplitude ratio into decibels and percentage change. Kinematic Displacement Calculator Calculate one-dimensional displacement, final position, final velocity, and average velocity under constant acceleration. Cylinder Density Calculator Calculate the volume and density of a uniform solid cylinder from its mass, diameter, and height. Magnetic Declination Bearing Correction Calculator Convert a magnetic bearing to a true bearing using a supplied local magnetic declination value. Circular Orbit Period and Speed Calculator Estimate circular-orbit period, speed, and local escape speed from central mass and orbital radius. Electric Dipole Moment Calculator Calculate the magnitude of an electric dipole moment from separated charge and charge-center distance. Relativistic Length Contraction Calculator Calculate the length observed parallel to motion when an object travels at a chosen fraction of light speed. Rocket Engine Thrust Calculator Estimate rocket thrust from exhaust mass flow, exhaust velocity, nozzle area, and exit-to-ambient pressure difference. Marine Propeller Slip Calculator Estimate apparent propeller slip from engine speed, gear ratio, propeller pitch, and measured boat speed. Fully Restrained Thermal Stress Calculator Estimate axial thermal stress, thermal strain, and free expansion for a linearly elastic member that cannot expand. Virtual Temperature Calculator Estimate meteorological virtual temperature from air temperature and water-vapor mixing ratio. CFD y⁺ Wall-Distance Calculator Calculate dimensionless wall distance y⁺ from first-cell distance, friction velocity, and kinematic viscosity. Density from Mass and Volume Calculator Calculate density and specific volume from a mass and volume measured on the same unit basis. Electrical Power Calculator Estimate real power, apparent power, energy, and resistance from voltage, current, power factor, and operating time. Frequency to Wavelength Calculator Convert frequency and wave speed into wavelength, period, and wavenumber for a stated medium or signal. Rolling Resistance Force and Power Calculator Estimate level-road rolling-resistance force, power, and work from mass, coefficient, speed, and distance. Column Slenderness Ratio Calculator Calculate effective length and KL/r slenderness ratio from unsupported length, effective-length factor, and radius of gyration. Reaction Time Distance Calculator Estimate distance traveled during a stated reaction time at a stated speed. Speed of Sound in Dry Air Calculator Estimate the speed of sound in dry air from temperature using a stated near-room-temperature approximation. Moisture Content Wet and Dry Basis Calculator Calculate water mass and moisture content on wet and dry bases from wet and dry sample masses. Gold Volume to Weight Estimate Calculator Estimate pure-gold mass equivalent and troy ounces from volume and an entered purity percentage. Generator Useful Power Calculator Estimate useful real output and energy from a generator apparent-power rating, power factor, efficiency, and operating time. Supersonic Isentropic Flow Calculator Calculate ideal supersonic flow ratios, critical-area ratio, Mach angle, and Prandtl-Meyer angle from Mach number and heat-capacity ratio. Weak Oblique Shock Calculator Estimate weak attached-shock angle and downstream flow ratios from upstream Mach number, turning angle, and specific-heat ratio. Prandtl-Meyer Expansion Calculator Calculate downstream Mach number and ideal pressure, temperature, and density ratios through a supersonic expansion fan. Shear-Wave Velocity Calculator Estimate shear-wave speed in a material from shear modulus and density, with an optional travel-time scenario. Thermal Conductivity Heat-Flow Calculator Estimate steady one-dimensional conductive heat flow through a slab from conductivity, area, thickness, and temperature difference. Rotational Stiffness Calculator Estimate a linear torsional stiffness and ideal elastic energy from applied torque and angular displacement. Spherical Capacitor Calculator Calculate ideal capacitance and stored energy for two concentric spherical conductors with a specified dielectric. Intrinsic Semiconductor Carrier Concentration Calculator Estimate equilibrium intrinsic carrier concentration from effective density of states, band gap, and temperature. Mixed Air Temperature Calculator Calculate the ideal adiabatic mixed-air temperature from two mass-flow streams, temperatures, and specific heats. Frequency and Period Calculator Calculate frequency, period, angular frequency, and a wavelength-based wave speed from a counted cycle interval. Sensible Heat Calculator Calculate the energy needed to change a sample temperature from its mass, specific heat capacity, and temperature interval. Spring Rate and Natural Frequency Calculator Estimate linear spring rate, stored elastic energy, and ideal small-oscillation frequency from force and deflection. Stress Concentration Factor Calculator Estimate an elastic local peak stress and a simple allowable-stress ratio from nominal stress and an entered Kt factor. Twist Rate Calculator Convert a signed number of revolutions over a length into turns per metre, radians per metre, degrees per millimetre, and pitch. Thrust-to-Weight Ratio Calculator Calculate thrust-to-weight ratio, excess thrust, and an ideal no-drag vertical acceleration estimate from force inputs. Age on Other Planets Calculator Convert an Earth age into planetary years and completed birthdays using the selected planet’s sidereal orbital period. Steady Conduction Heat Transfer Calculator Estimate steady heat-transfer rate and energy through a flat layer from conductivity, area, temperature difference, thickness, and time. Telescope Magnification and Exit Pupil Calculator Calculate visual telescope magnification, exit pupil, and focal ratio from objective and eyepiece dimensions. Preliminary Wind Load Force Calculator Estimate dynamic wind pressure and a drag-based force from air density, wind speed, exposed area, drag coefficient, and an optional exposure factor. Solid Shaft Torsional Size Calculator Estimate the required diameter and torque capacity of a solid circular shaft from torque, allowable shear stress, and a safety factor. Enhancement MOSFET Operating Point Calculator Estimate an ideal n-channel enhancement MOSFET current, region, transconductance, and drain power from the square-law model. BJT Voltage-Divider Bias Calculator Estimate the base, collector, and emitter currents and the Q-point of an NPN transistor using a voltage-divider bias model. Single-Phase Motor Power-Factor Capacitor Calculator Estimate the shunt capacitor needed to move a single-phase inductive load from an entered power factor to a higher target. Ideal-Gas Thermodynamic Process Calculator Compare final state, boundary work, internal-energy change, and heat transfer for an ideal-gas isothermal, isobaric, isochoric, or adiabatic process. True Strain Calculator Calculate logarithmic true strain, engineering strain, stretch ratio, and percentage change from original and final lengths. Shear Modulus from Stress and Strain Calculator Calculate an apparent shear modulus from entered shear stress and dimensionless shear strain. Muzzle Velocity from Projectile Energy Calculator Calculate the ideal exit speed of a projectile or object from its mass and kinetic energy, with momentum and unit conversions shown. kVA to Amperage Calculator Convert apparent power, RMS voltage, and single- or balanced three-phase selection into an estimated line current. MOSFET Threshold Voltage from Operating Point Calculator Estimate an ideal n-channel MOSFET threshold voltage from a measured or specified drain current, square-law parameter, and gate-to-source voltage. AWG Wire Gauge Geometry and Resistance Calculator Convert an American Wire Gauge number into conductor diameter, cross-sectional area, and estimated resistance for a selected material and length. Volts to Electron-Volts Energy Calculator Calculate the energy change in electron-volts and joules from a potential difference and a charge expressed in elementary-charge units. Latitude and Longitude to UTM Converter Convert WGS84 latitude and longitude into a Universal Transverse Mercator zone, latitude band, easting, and northing for locations between 80°S and 84°N. Psychrometric Moist-Air Properties Calculator Estimate saturation pressure, vapor pressure, humidity ratio, dew point, specific volume, and moist-air enthalpy from dry-bulb temperature, relative humidity, and air pressure. Spring Rate Unit Converter Convert a spring stiffness value between newtons per metre, newtons per millimetre, pound-force per inch or foot, kilopounds per inch, kilogram-force per millimetre, and equivalent joules per square metre. Pure Water Density by Temperature Calculator Estimate pure-water density at atmospheric pressure from temperature, then calculate the mass of a chosen water volume and compare an object's density with the water state. Rolling Cylinder Ramp Race Calculator Compare the ideal acceleration, final speed, and travel time of a solid cylinder, cylindrical tube, or thin shell rolling down a ramp from rest. Quarter-Mile Performance Estimate Estimate quarter-mile elapsed time and trap speed from vehicle mass, engine power, and a selected empirical drag-racing correlation, with metric and imperial inputs supported. Water Heating Energy and Time Calculator Estimate the sensible energy, input energy, and heating time for a stated mass of liquid water when the heater power and efficiency are known. Refrigeration Ton to Kilowatt Converter Convert refrigeration capacity in tons of cooling into kilowatts and British thermal units per hour without confusing cooling capacity with electrical input power. SiPM Photon Detection Efficiency Calculator Estimate photon detection efficiency from responsivity, wavelength, gain, optical crosstalk, and afterpulsing using a transparent SiPM measurement relation. Relativistic Bug–Rivet Paradox Calculator Explore length contraction, information-travel time, tip travel, and critical speed ratios in a bounded educational bug–rivet thought experiment. Universe Expansion Scenario Model Integrate a bounded dimensionless scale-factor scenario from present time using matter, radiation, curvature, dark-energy fractions, and a chosen Hubble constant. Actual and Theoretical Yield Calculator Calculate percent yield and the difference between theoretical and recovered product mass from an explicit chemistry experiment. Standard Temperature and Pressure Gas Calculator Compare common standard-state conventions by calculating ideal-gas volume, mass, density, and molar volume for a chosen amount of gas. Newton’s Third-Law Force Pair Calculator Resolve one interaction force into components and return the equal, opposite force on the other body without confusing the pair with forces on one body. SUVAT Constant-Acceleration Calculator Calculate final velocity, displacement, final position, and average velocity for one-dimensional motion with constant acceleration. CNC Machining Speeds and Feeds Calculator Estimate spindle speed and feed rate from cutting speed, tool diameter, flute count, chip load, and a user-entered machine RPM limit. Circular Shaft Torsional Constant Calculator Calculate the polar torsional constant, elastic torsional stiffness, twist, and surface shear stress for a solid circular shaft. Torsional Spring Torque and Energy Calculator Calculate elastic torque, total torque with an entered preload, angular deflection, and stored spring energy for an ideal torsional spring. Rockwell C and Vickers Hardness Estimate Estimate a Rockwell C or Vickers hardness value for the ASTM non-austenitic-steel equation scope, with the material and validity limits kept visible. Earthquake Magnitude and Energy Scenario Calculator Estimate the approximate energy associated with a moment magnitude and compare the energy and amplitude ratios between two magnitudes. Corrosion Thickness-Loss Scenario Calculator Estimate linear material thickness loss from an entered corrosion penetration rate and test how long a component remains above a chosen minimum thickness. Vapor Pressure Deficit Calculator Estimate saturation vapor pressure, actual vapor pressure, and vapor pressure deficit from air temperature and relative humidity using a transparent FAO-style approximation. Horse Weight Estimate Calculator Estimate a horse's body weight from heart-girth circumference and body length using a clearly labeled measurement-based equation and life-stage divisor. Tree Diameter from Circumference Calculator Convert a measured tree circumference into diameter, radius, and common forestry units while keeping the measurement height visible. Tree Age Growth-Factor Estimate Estimate a tree's approximate age from diameter and a user-selected growth factor, with a visible uncertainty band rather than a false exact age. Vegetable Yield Planning Calculator Estimate a garden harvest from growing area, an entered yield density, and the number of planned harvest cycles without pretending every crop or climate has one fixed yield. Trihybrid Cross Probability Calculator Calculate the eight dominant and recessive phenotype probabilities for three independently assorting traits from six parent genotype inputs. Protein Molecular Weight from Sequence Calculator Estimate a protein's average molecular mass from a one-letter amino-acid sequence, accounting for peptide-bond water loss and reporting daltons and kilodaltons. MLVSS Wastewater Solids Calculator Calculate mixed-liquor volatile suspended solids concentration, inert suspended solids, and total volatile solids mass from MLSS, volatile fraction, and basin volume. Horse Gestation Date Range Calculator Estimate average, early-bound, and late-bound foaling dates from a breeding date and explicit horse gestation intervals. Engine Compression Ratio Calculator Calculate swept displacement, total cylinder volume, and nominal static compression ratio from bore, stroke, cylinder count, and clearance volume. Simplified Circuit Breaker Load Estimate Estimate a planning minimum overcurrent-device rating from continuous and noncontinuous loads, then round to a common standard rating. Light-Year Distance and Travel-Time Converter Convert a distance in light-years to metres, kilometres, astronomical units, parsecs, and the corresponding light-travel time. Current-Loop Magnetic Dipole Moment Calculator Calculate the magnetic dipole moment of a multi-turn current loop and its ideal torque and potential energy in a uniform magnetic field. Circular Shaft Torsional Stiffness Calculator Estimate the torsional stiffness, twist torque, and outer-fiber shear stress of a circular shaft from material rigidity and geometry. Watts to Lux Estimate from Luminous Efficacy Estimate illuminance from electrical power, a supplied luminous efficacy, utilization factor, and illuminated area. Buoyancy Experiment Density Calculator Use mass readings in air and while fully submerged to estimate apparent mass loss, buoyant force, displaced volume, and object density. Pendulum Kinetic Energy Calculator Estimate height drop, ideal speed, potential-energy loss, and kinetic-energy gain for a pendulum released from rest at one angle. Earth Curvature Geometry Comparator Compare the exact spherical-surface drop below a local tangent plane with the small-distance approximation and a flat-plane zero-drop reference. Capillary-Tube Pressure-Drop Screening Calculator Estimate single-phase frictional pressure drop, Reynolds number, velocity, and head loss in a small tube from flow, fluid properties, length, diameter, and roughness. Smartphone Projector Lens Geometry Calculator Estimate screen distance, signed magnification, projected image height, and orientation from a thin-lens smartphone projector geometry. Lever Mechanical Advantage Calculator Estimate ideal and efficiency-adjusted mechanical advantage, output force, and work for a simple lever. Sphere Density from Mass and Diameter Calculate the volume, average density, weight, and specific gravity of an ideal sphere from mass and diameter. Air Water-Vapor Mixing Ratio Calculator Calculate water-vapor mixing ratio, mass fractions, and dry-air pressure from vapor and total pressure. Control-Valve Cv Requirement Calculator Compare required and rated liquid valve Cv from target flow, pressure drop, and specific gravity. Impact Test Energy Screening Calculator Estimate impact energy, absorbed energy, average stopping force, momentum, and area-normalized energy in a simplified test scenario. Grams to Moles Chemistry Calculator Convert a measured mass and a supplied molar mass into moles, millimoles, and an estimated count of specified entities. Molecular Weight from Chemical Formula Calculator Parse a chemical formula with element counts and brackets to estimate molar mass, relative molecular mass, and total atoms per formula unit. Moles to Atoms Calculator Convert moles of molecules, formula units, or another specified entity into entity count, individual atom count, and moles of atoms. Percent Solution Concentration Calculator Calculate w/w, w/v, or v/v solution concentration from a solute amount and the total solution amount using matching basis units. Solution Dilution Calculator Use C₁V₁ = C₂V₂ to check an entered stock volume, calculate the stock volume needed for a target concentration, and find the diluent volume. Elliptical Impact Angle Estimator Estimate an acute angle from the measured major and minor axes of an ellipse-shaped impact mark, with explicit forensic limitations. Hardy–Weinberg Equilibrium Calculator Estimate allele frequencies, expected two-allele genotype counts, and a chi-square screening value from observed genotype counts. Projectile Kinetic Energy Calculator Calculate classical kinetic energy and momentum from projectile mass, speed, and a stated count for an educational physics worksheet. DC Resistor Wattage Calculator Solve a single-resistor DC circuit from any selected pair of voltage, current, and resistance values, then show dissipated power and a visible planning margin. Kilograms to Newtons (Mass to Weight) Calculator Convert a mass into gravitational force using an explicitly entered local gravitational acceleration. Normal Stress Calculator Calculate average axial normal stress from an applied force and loaded cross-sectional area. Capacitor Charge and Energy Calculator Calculate stored charge and electrostatic energy from capacitance and voltage for an ideal capacitor. Vertical Rope Tension Calculator Estimate the tension in an ideal vertical rope supporting a mass with a stated vertical acceleration. Ohm's Law Current Calculator Calculate current through an ideal ohmic resistance from voltage and resistance, with power and conductance shown as supporting results. Average Shear Stress Calculator Calculate average shear stress from a shear force and resisting area, with Pa, kPa, and MPa outputs. Wattage to Amperage Calculator Estimate electrical current from real power, voltage, and power factor for a single-phase or balanced three-phase model. Horizontal Projectile Motion Calculator Calculate flight time, horizontal range, and impact speed for an object launched horizontally from a height. Local Sidereal Time Calculator Calculate Julian date, approximate Greenwich mean sidereal time, and local mean sidereal time from a UTC date, time, and longitude. Rain-to-Snow Equivalent Calculator Estimate fresh and settled snow depth from liquid-equivalent precipitation, a chosen snow-to-liquid ratio, and a transparent settling allowance. Flight Cosmic-Radiation Exposure Estimate Estimate cumulative effective dose from an entered average in-flight dose rate, flight duration, number of flights, and optional scenario reduction. Cat Age to Human-Equivalent Years Calculator Estimate a cat's human-equivalent age from completed years and months using a transparent staged age convention and an explicit life-stage band. Cat Pregnancy Date-Range Calculator Estimate early, typical, and late planning dates from a cat breeding or ovulation reference date and editable gestation intervals. Bird Age to Human-Equivalent Years Calculator Map a bird's chronological age onto a user-supplied human reference lifespan while keeping the species lifespan assumption visible. Protein Concentration from A280 Calculator Estimate protein concentration from a corrected 280 nm absorbance, path length, dilution factor, and protein-specific 0.1% extinction coefficient. Wastewater Flow Planning Calculator Estimate average flow, infiltration and inflow allowance, peak design flow, and a simple retention volume from population and entered planning assumptions. Saturated Liquid Ethylene Density Calculator Interpolate a NIST table of saturated-liquid ethylene molar density from 105 K to 160 K and convert it to an approximate mass density. BTU per Hour to Refrigeration Tons Calculator Convert cooling capacity in BTU per hour to refrigeration tons, kilowatts, and daily heat-removal equivalents. Specific Gravity from Density Calculator Calculate specific gravity from a material density and an explicit reference density, with a sample-mass comparison. Particle Speed from Kinetic Energy Calculator Solve the classical non-relativistic kinetic-energy equation for particle speed and momentum from energy and mass. Two-Node Spring Stiffness Matrix Calculator Build the local 2×2 stiffness matrix for a linear spring element and calculate nodal forces, extension, and strain energy. Moist-Air Mixing Calculator Estimate the mixed dry-bulb temperature, humidity ratio, enthalpy, and relative humidity for two adiabatically mixed air streams. Olbers’ Paradox Finite Shell Demonstration Estimate the finite shell contribution and cumulative flux in a simplified uniform-star model to explore why an infinite static universe creates a paradox. Weight on Planets and the Moon How much a mass weighs under each body's surface gravity, in newtons. Friction Force Coulomb friction force from coefficient μ and normal force. Hydraulic Pressure Pressure from an applied force over a piston area, in pascals and kilopascals. Half-Life Remaining Quantity What remains of a decaying sample after a given elapsed time. Percent Concentration (w/w, w/v) Weight/weight or weight/volume percent from solute and total solution. Gas Volume at STP Litres and molecule count for moles of ideal gas at STP. Punnett Square (Single Trait) Offspring genotype odds for a one-gene cross of two parents. Microscope Magnification Total magnification from ocular and objective lenses. CFU per mL (Plate Count) Viable concentration from colonies, plated volume, and dilution. Average Speed Mean travel speed from distance and time, in km/h and m/s. Energy Efficiency Energy efficiency from useful output over total input. Molar Mass Molar mass of a formula with per-element mass breakdown. Buffer pH Buffer pH from pKa and base/acid concentrations. Cell Size from Field of View Mean cell size from microscope field diameter and cell count. Pascal's Hydraulic Lift Output force from input force and two piston areas. Impulse and Momentum Change Impulse, velocity change, and final velocity from force and time. Logistic Population Growth Capped growth from carrying capacity and intrinsic rate. Percent Composition Molar mass and element mass percents from a formula. Decibel Level Comparison Converts an intensity ratio into decibels relative to a reference. Mole Fraction Calculate one component's mole fraction and percentage from its amount and the total amount of substance. Partial Pressure Calculate a component gas's partial pressure from total pressure and its mole fraction. Gibbs Free Energy Change Estimate Gibbs free-energy change from enthalpy change, temperature, and entropy change. Moles to Particles Convert an amount in moles to an estimated number of representative particles using Avogadro's constant. Centripetal Force Calculate the inward radial force needed for an object moving at a stated speed along a circular path. Buoyant Force Calculate the upward buoyant-force magnitude from fluid density, displaced volume, and local gravitational acceleration. Photon Energy Calculate photon energy from wavelength using Planck's constant and the speed of light. Activation Energy from Two Rates Estimate an apparent activation energy from two rate constants measured at different absolute temperatures. Air-Fuel Ratio Calculate the mass ratio of air to fuel and its reciprocal fuel-to-air ratio for a stated mixture. Alligation Mixture Find the masses of a low-concentration and high-concentration material needed to make a target concentration. Arrhenius Equation Estimate a rate constant from a pre-exponential factor, activation energy, and absolute temperature. Atom Economy Calculate the theoretical percentage of reactant mass incorporated into a desired product. Beer-Lambert Law Calculate absorbance, transmittance, and percent transmittance from molar absorptivity, path length, and concentration. Boiling-Point Elevation Estimate the boiling-point increase caused by a dissolved solute using molality and the solvent constant. Molecular-Orbital Bond Order Calculate a simple molecular-orbital bond order from bonding and antibonding electron counts. Weighted Average Atomic Mass Calculate the weighted average mass of a two-isotope mixture from isotope masses and percentage abundances. Weak-Acid Buffer Capacity Estimate the buffer capacity of a monoprotic weak-acid system from total concentration, pKa, and pH. de Broglie Wavelength Calculate the matter-wave wavelength associated with a supplied particle momentum. Electric Field of a Point Charge Calculate the electric-field magnitude at a distance from an ideal point charge in vacuum. Electric Potential of a Point Charge Calculate the electric potential at a distance from an ideal point charge. Magnetic Field of a Straight Current-Carrying Wire Calculate the magnetic-field magnitude around an ideal long straight wire carrying current. Simple Pendulum Frequency Estimate the oscillation frequency of an ideal simple pendulum from its length and local gravity. Ideal LC Resonant Frequency Calculate the natural resonant frequency of an ideal inductor-capacitor circuit. Ideal Rocket Delta-v Estimate ideal rocket velocity change from specific impulse and initial and final mass. Photoelectric Effect Calculate the maximum photoelectron kinetic energy from wavelength and a material work function. Allele Frequency Calculate the frequencies of two alleles from their observed copy counts in a population sample. Daily Light Integral Estimate daily photosynthetic photon delivery from average PPFD and illuminated hours. DNA to mRNA Sequence Transcribe a DNA sequence into an mRNA sequence using an explicit coding or template strand choice. Capacitive Reactance Calculate the magnitude of a capacitor's opposition to sinusoidal AC at a chosen frequency. Inductive Reactance Calculate the magnitude of an inductor's opposition to sinusoidal AC at a chosen frequency. Capacitor Stored Energy Calculate the ideal energy and charge stored by a capacitor at a supplied voltage. Capacitors in Series Find the equivalent capacitance of two or more ideal capacitors connected in series. Parallel Capacitors Find the equivalent capacitance of two or more ideal capacitors connected in parallel. Inductors in Series Find the equivalent inductance of two or more ideal uncoupled inductors connected in series. Inductors in Parallel Find the equivalent inductance of two or more ideal uncoupled inductors connected in parallel. Current Divider Calculate the currents in two parallel resistive branches from total current and branch resistances. Voltage Divider Calculate the output voltage and current of an unloaded two-resistor series divider. RC Circuit Charging Estimate capacitor voltage, charge, and current during ideal charging from a constant-voltage step. Series RLC Impedance Calculate the magnitude, net reactance, and phase angle of an ideal series RLC circuit at one frequency. Source Internal Resistance Calculate terminal voltage and power losses for an ideal source with internal resistance delivering current. Acres Per Hour Calculate an area-completion rate in acres per hour from a nonnegative area and a positive elapsed time. Animal Mortality Rate Calculate an interval mortality rate per 1,000 and as a percentage from deaths and the number surviving at the interval start. Annealing Temperature Quick Screen Estimate a short oligo melting temperature with the educational Wallace count rule, subtract an offset for a screening annealing temperature, and report GC percentage. Bacteria Growth Calculate continuous idealized population growth from an initial population, a positive doubling time, and elapsed hours. Basal Area From Diameter Estimate circular cross-sectional area per stem and in total from a supplied diameter and a safe stem count. Bulb Spacing Area Estimate Estimate the number of equally spaced bulbs for a rectangular bed using a square-grid footprint and a whole-unit ceiling. Cattle Per Acre Calculate a descriptive cattle-per-acre rate from a safe whole-number cattle count and positive acreage. Cell Doubling Time From Observations Estimate an idealized doubling time from positive observed populations, a larger final observation, and elapsed hours. Corn Harvest Density Calculate descriptive harvested corn mass per hectare from an entered mass and harvested area. Dihybrid Cross Punnett Square Calculate genotype and simplified phenotype percentages for a two-locus cross using nine canonical parent genotypes. DNA Concentration Calculate DNA mass concentration from an entered mass and sample volume, with equivalent ng/uL and ug/mL outputs. DNA Copy Number From Mass Estimate the number of double-stranded DNA molecules from mass and a safe whole-number base-pair length. Shannon Diversity Index Calculate descriptive Shannon diversity and evenness from a bounded list of entered species or group counts. Hydroelectric Power Calculate idealized hydraulic and delivered electrical power from entered water flow, hydraulic head, and efficiency. Solar Panel Wattage Calculate idealized instantaneous solar-panel power from entered irradiance, panel area, and conversion efficiency. Wind Turbine Power Calculate idealized kinetic wind power and estimated turbine power from entered air density, swept area, wind speed, and power coefficient. Torque from Force and Lever Arm Calculate the magnitude of torque from a force, lever-arm length, and the angle between them. Angular Momentum of a Point Mass Calculate angular momentum magnitude for a point mass moving tangentially at a stated radius and speed. Rotational Kinetic Energy Calculate the rotational kinetic energy of an ideal rigid body from its moment of inertia and angular speed. Elastic Potential Energy Calculate the elastic potential energy stored in an ideal linear spring from its spring constant and displacement. Gravitational Force Between Two Point Masses Calculate the magnitude of Newtonian gravitational force between two point masses at a stated separation. Escape Velocity Calculate the classical escape velocity at the surface of an ideal spherical body from its mass and radius. Latent Heat Calculate the energy required for a phase change from mass and specific latent heat. Linear Thermal Expansion Calculate length change and final length from initial length, linear expansion coefficient, and temperature change. Coulomb's Law Calculate the magnitude and attraction or repulsion relationship for two point charges at a stated separation. Magnetic Force on a Current-Carrying Wire Calculate the magnetic-force magnitude on a straight current-carrying wire in a uniform magnetic field. Snell's Law Calculate the refracted angle from two refractive indices and an incident angle, including a total-internal-reflection result when appropriate. Thin Lens Equation Calculate image distance and magnification from a signed focal length and positive object distance. Diffraction-Limited Angular Resolution Calculate the Rayleigh diffraction-limit angular resolution of a circular aperture from wavelength and diameter. Stefan-Boltzmann Law Calculate ideal thermal-radiation power from emissivity, radiating area, and absolute temperature. Wien's Displacement Law Calculate the ideal blackbody peak wavelength from absolute temperature. Angular Acceleration Calculate average angular acceleration from initial angular velocity, final angular velocity, and a positive time interval. G-Force from Acceleration Express a supplied acceleration magnitude as a multiple of standard gravity without calculating force in newtons. Stellar Parallax Distance Calculate an astronomical distance from a positive stellar parallax entered in arcseconds, reporting parsecs and light-years. Circular Two-Body Orbital Velocity Calculate the Newtonian relative speed for two positive masses in a circular orbit at a stated center-to-center separation. Special-Relativistic Time Dilation Calculate proper elapsed time from a coordinate-time interval and a subluminal speed using the special-relativistic inertial-clock relation. Empirical Formula Determine an empirical formula from mass percentages for two to twelve supported elements. Molality Calculate solution molality from solute amount and the mass of solvent in kilograms. Freezing-Point Depression Estimate the freezing-point decrease and solution temperature for a dilute ideal solution. Raoult's Law Calculate a volatile solvent mole fraction, ideal solution vapor pressure, and pressure lowering. PPM to Molarity Convert a mass-based ppm concentration into molarity and mass concentration using solution density. Mass-Energy Equivalence (E=mc^2) Calculate the rest energy represented by a mass using the special-relativity equivalence E0 = mc^2. Relativistic Kinetic Energy Calculate kinetic energy from mass and speed as a fraction of the speed of light using the Lorentz factor. Relativistic Velocity Addition Combine two signed collinear subluminal velocities using the special-relativistic velocity-addition formula. Hooke's Law Spring Force Calculate the ideal restoring force and its magnitude from a linear spring constant and signed displacement. Carnot Efficiency Limit Calculate the ideal reversible Carnot efficiency limit from hot- and cold-reservoir temperatures in kelvins. Index of Refraction from Light Speed Calculate a medium's refractive index and light-speed fraction from its supplied light speed. Beat Frequency Calculate the ideal beat frequency produced by two entered frequencies. Doppler Effect Moving Source Calculate the observed frequency and shift for a stationary observer and a one-dimensional moving source in a still medium. Heisenberg Position-Momentum Uncertainty Calculate the minimum momentum uncertainty associated with a positive position uncertainty using the one-dimensional Heisenberg bound. Two-Body Thermal Equilibrium Temperature Calculate the final equilibrium temperature and signed heat transfer for two bodies sharing heat in an isolated constant-specific-heat model. Cyclotron Frequency, Angular Frequency, and Period Calculate the angular frequency, ordinary frequency, and period of a signed charged particle in a positive magnetic field. Malus's Law Polarized Intensity Calculate transmitted intensity and the ideal transmission fraction for linearly polarized light passing through an analyzer at a stated angle. Kepler's Third Law Two-Body Orbital Period Calculate a Newtonian two-body orbital period in seconds and days from semimajor axis and primary and secondary masses. Voltage Drop Calculator Calculate two-conductor voltage drop from current, one-way length, resistance, and source voltage. Wind Chill Calculator Calculate the National Weather Service wind-chill index for Fahrenheit air temperatures and wind speeds. Heat Index Calculator Calculate the National Weather Service Rothfusz heat-index estimate from Fahrenheit temperature and humidity. Dew Point Calculator Estimate dew point from Celsius air temperature and relative humidity with the Magnus approximation. Torque and Horsepower Calculator Convert torque and rotational speed into watts, kilowatts, and mechanical horsepower.

Digital Task Water Footprint Scenario Calculator Estimate a supplied water footprint for repeated digital tasks from water per task and task count. Books Versus E-Books Emission Scenario Calculator Compare supplied production and use emissions for paper books and e-books. Car Versus Bicycle Trip Emission Calculator Compare supplied trip emissions for a car and a bicycle over repeated trips. Logistic Carrying Capacity Step Calculator Estimate one bounded population step under a logistic growth model with a supplied carrying capacity. Breathing Carbon Dioxide Scenario Calculator Estimate carbon dioxide mass from people, hours, and a supplied per-person emission rate. Digital Transaction Energy and Carbon Scenario Calculator Estimate energy and carbon from transaction count, energy per transaction, and an emission factor. Hand Dryer Versus Paper Towel Scenario Calculator Compare supplied energy and paper emissions for repeated hand-drying events. Kaya Identity Emissions Scenario Calculator Calculate an emissions scenario from population, GDP per person, energy intensity, and carbon intensity. Lotka-Volterra Population Step Calculator Calculate one simplified predator-prey population step from supplied interaction parameters. Meat Portion Emission Scenario Calculator Estimate total emissions from portions, portion mass, and a supplied meat emission factor. Passive Building Annual Energy Scenario Calculator Estimate annual energy use and emissions from floor area, energy demand intensity, and an electricity factor. Plug-In Hybrid Emission Scenario Calculator Estimate total energy and emissions for electric and fuel travel shares supplied by the user. Plastic Use Footprint Scenario Calculator Calculate total plastic mass and unrecycled mass from item count, item weight, and recycling fraction. Plastic Reduction Avoided-Item Calculator Calculate avoided items and mass when a baseline use rate is reduced over a selected number of days. Solar Panel Annual Energy Scenario Calculator Estimate annual solar energy from irradiance, panel area, efficiency, and days in the scenario. Tap Water Use Calculator Calculate water volume from flow rate, daily minutes, and number of days. Tree Carbon Benefit Scenario Calculator Estimate cumulative carbon benefit from tree count, annual benefit per tree, and years. Plant-Based Meal Emission Scenario Calculator Estimate emissions difference when a share of meals changes from an animal-based factor to a plant-based factor. Wind Turbine Energy Revenue Scenario Calculator Estimate gross revenue and operating margin from turbine power, capacity factor, price, and operating cost. Reusable Versus Disposable Tree Scenario Calculator Compare supplied emissions for reusable and disposable seasonal trees over multiple seasons. Hydraulic Retention Time Calculator Calculate the average hydraulic residence time of a tank, basin, reactor, or pond from its working volume and flow rate. Fish Mercury Exposure Screening Calculator Estimate average methylmercury dose from fish concentration, portion size, and weekly frequency, then compare the arithmetic with an entered screening reference dose. PAH Benzo[a]pyrene-Equivalent Calculator Combine polycyclic aromatic hydrocarbon concentrations with a documented toxic-equivalency factor list and show the weighted benzo[a]pyrene-equivalent total. Plastic Flow Mass-Balance Calculator Balance an annual plastic input against recycled, incinerated, landfilled, and leaked flows, then show recycling, leakage, and unaccounted shares. Major Event Sustainability Emissions Calculator Build a transparent major-event emissions scenario from construction, travel, accommodation, operations, and other categories, then apply a planning reduction percentage. COVID-Era Before-and-After Pollution Calculator Compare measured pollutant concentrations before and after a COVID-era intervention period and calculate percentage change and concentration-time differences without making a health claim. Tree Value Discounted-Cash-Flow Scenario Calculator Estimate the present value of a tree or timber scenario from harvest revenue, thinning revenue, management costs, upfront cost, timing, and an entered discount rate.

Length Converter Convert metric and international customary lengths, including statute and nautical miles, using defined factors. Weight and Mass Converter Convert kilograms, grams, milligrams, metric tonnes, pounds, ounces, and stones as units of mass. Temperature Converter Convert absolute temperatures among Celsius, Fahrenheit, and Kelvin, with absolute-zero validation. Area Converter Convert square metric and customary units, hectares, and international acres without confusing linear and area factors. Volume Converter Convert liters, milliliters, cubic units, US liquid gallons, and Imperial gallons with explicit gallon definitions. Speed Converter Convert meters per second, kilometers per hour, miles per hour, feet per second, and knots. Angle Converter (Degrees and Radians) Convert angles between degrees and radians. Dimensional Weight and Chargeable Weight Calculator Estimate volumetric shipping weight and choose the larger of actual and dimensional weight using a user-supplied divisor. Acres to Ares Conversion Calculator Convert an area in acres to ares and square metres using an exact metric relationship. Angle Degrees Radians and Turns Converter Convert a degree angle into radians and full turns. Angstroms to Nanometres Converter Convert a length in angstroms to nanometres and metres. Atmospheres to Pascals Converter Convert standard atmospheres to pascals and kilopascals. Bar to PSI Converter Convert pressure in bar to pounds per square inch and kilopascals. Binary to Hexadecimal Converter Convert a nonnegative binary integer into hexadecimal and decimal representations. Bytes Bits and Decimal Storage Converter Convert a byte count into bits, decimal kilobytes, and decimal megabytes. Celsius to Fahrenheit Converter Convert a Celsius temperature to Fahrenheit and Kelvin. Centimetres to Feet and Inches Converter Convert centimetres to total inches and a feet-plus-inches display. Decimal Integer to Hexadecimal Converter Convert a signed whole-number value into hexadecimal notation. Degrees to Radians Converter Convert an angle in degrees to radians and turns. dBm to Watts Converter Convert a power level in dBm to watts and milliwatts. Fuel Economy L/100 km to km/L and MPG Converter Convert metric fuel economy in litres per 100 kilometres to kilometres per litre and US miles per gallon. Knots to Kilometres per Hour Converter Convert speed in nautical knots to kilometres per hour and miles per hour. Kilometres to Miles Converter Convert a distance in kilometres to statute miles and metres. Decimal Inches to Fractional Inches Converter Convert decimal inches to the nearest fraction using a selected denominator. Kelvin to Celsius Converter Convert an absolute temperature in kelvin to Celsius and Fahrenheit. Kilograms to Pounds Converter Convert mass in kilograms to international pounds and grams. Kilopascals to PSI Converter Convert pressure in kilopascals to pounds per square inch and bar. Litres to Cubic Centimetres Converter Convert liquid volume in litres to cubic centimetres and millilitres. Acres to Hectares Converter Convert international acres into hectares and square metres for land-area planning. Ares to Hectares Converter Convert ares into hectares and square metres using the metric land-area relationship. CCF to Gallons Converter Convert hundred cubic feet of gas or water volume into cubic feet, US gallons, and litres. CCF to Therms Calculator Estimate natural-gas energy in therms and kilowatt-hours from CCF using an explicit heat-content input. Crore to Lakh Converter Convert a value expressed in crores into lakhs and the underlying count of units. Crore to Million Converter Convert crores into millions and billions while keeping the underlying count visible. Million to Lakh Converter Convert millions into lakhs and crores for comparing international and South Asian number formats. Gaj to Square-Yard Converter Convert a regional gaj area into square yards, square feet, and square metres using a visible local factor. Katha to Square-Feet Converter Convert katha into square feet, square metres, and acres with a user-supplied regional katha factor. Mesh to Micron Opening Converter Estimate sieve pitch and opening size from mesh count and an explicit wire diameter. PPM to Milligrams per Litre Converter Convert a dilute mass concentration in ppm into mg/L and g/L using solution density. Price per Litre to Price per Gallon Converter Convert a unit price per litre into a price per US or imperial gallon without changing the currency. Paper Quantity and Ream Calculator Estimate sheets and reams from page count, copies, print sides, and a visible waste allowance. Pixels to Inches Converter Convert a pixel dimension into inches and centimetres from an explicit pixels-per-inch resolution. Pixels to em and rem Converter Convert a pixel value into em and rem units from the relevant parent and root font sizes. Drawing Scale Converter Convert a drawing length to a real length or reverse it using a clear 1-to-N scale denominator. Natural Gas Volume and Energy Converter Convert CCF, therms, cubic metres, and kilowatt-hours using explicit regional heat-content assumptions. Gallons to Mass and Tons Calculator Convert a liquid volume into kilograms and US short or metric tonnes from density and gallon definition. Cubic Yards to Tons Calculator Estimate material mass from cubic yards, bulk density, and a visible waste allowance in US short and metric tonnes. Grams to Fluid Ounces Converter Convert mass into millilitres and US or imperial fluid ounces using an explicit material density. Astronomical Unit Converter Convert astronomical units to metres, kilometres, and miles using the exact SI-defined astronomical unit. Barometric Pressure Unit Converter Convert a pressure reading in hectopascals into pascals, kilopascals, millimetres of mercury, inches of mercury, and psi. Billion to Trillion Converter Convert a decimal count expressed in billions into trillions, millions, and the underlying absolute count. Binary to Octal Converter Convert a nonnegative binary integer into decimal, octal, and hexadecimal representations. Cubic Centimetres to Millilitres Converter Convert cubic centimetres into millilitres, litres, and cubic metres using the exact volume equivalence. Celsius Temperature Converter Convert a Celsius temperature into Fahrenheit, kelvin, and Rankine while keeping absolute-zero validation visible. Centimetres to Kilometres Converter Convert a length in centimetres into metres, kilometres, millimetres, and inches. US Cups to Pints Converter Convert US customary cups into US pints, fluid ounces, quarts, and gallons with the serving-volume convention stated. Day to Time-Unit Converter Convert days into hours, minutes, seconds, and weeks using a fixed 24-hour day. Decagram to Gram Converter Convert decagrams into grams, kilograms, milligrams, and pounds using SI mass prefixes and the international pound. Decimal Degrees to DMS Converter Convert signed decimal degrees into degree, arcminute, arcsecond, and total-arcsecond components. Hectares to Acres Converter Convert hectares into square metres, square kilometres, international acres, and square feet. Knots to Miles per Hour Converter Convert nautical speed in knots into international miles per hour, kilometres per hour, and metres per second. Kilograms to Stones Converter Convert kilograms into UK stones, pounds, grams, and tonnes using the international avoirdupois pound. Kilobytes to Megabytes Converter Convert decimal kilobytes into bytes, megabytes, gigabytes, and binary mebibytes with the convention shown. Kilopascals to Atmospheres Converter Convert kilopascals into standard atmospheres, pascals, psi, torr, and millimetres of mercury. Litres to Centilitres Converter Convert litres into centilitres, millilitres, cubic centimetres, and cubic metres. Micrograms to Milligrams Converter Convert micrograms into milligrams, grams, nanograms, and kilograms while keeping SI prefixes explicit. Minutes to Decimal Time Converter Convert a duration in minutes into decimal hours, decimal days, seconds, and a readable hours-and-minutes value. Light-Year Distance Converter Convert light-years into kilometres, metres, astronomical units, and international miles using light speed and a Julian year. Acreage from Length and Width Calculate land area from rectangular dimensions and display the result in square feet, acres, and hectares. Binary and Decimal Base Converter Convert a nonnegative whole number between binary notation and decimal notation while keeping every bit visible. Hex Color to RGB and HSL Converter Decode a three-, six-, or eight-digit hexadecimal color into RGB, HSL, alpha, and relative luminance values. Cycles per Second and RPM Converter Convert a repeating rate between cycles per second, hertz, and revolutions per minute, then show the period. Cubic Centimeters to Grams Converter Convert a measured volume in cubic centimeters to mass when the material density is known. Cubic Feet to Pounds by Density Estimate material mass in pounds from cubic feet, density, and an optional waste or handling allowance. Land Cent to Square Meter Converter Convert the land-area unit cent to square meters, square feet, and acres using the one-cent-per-hundredth-acre convention. CGS and SI Unit Converter Convert compatible length, mass, force, and energy quantities between common CGS and SI units. Atmospheres Pressure Converter Convert standard atmospheres into pascals, kilopascals, bar, psi, and millimeters of mercury. Bar Gauge to PSIG Converter Convert a gauge pressure in bar to psig, absolute psi, and gauge kilopascals using an explicit atmospheric-pressure setting. Centimeters to Inches Converter Convert centimetres into international inches and companion metric and imperial length units. Acres to Square Feet Converter Convert international acres into square feet, square metres, hectares, and square yards with the unit basis stated. SCFM to SI Flow Converter Convert standard cubic feet per minute into cubic metres per second, cubic metres per hour, and litres per second. Pounds per Minute Flow Converter Convert mass flow in pounds per minute into kilograms per second, kilograms per hour, grams per second, and pounds per hour. Carat Weight Conversion Calculator Convert a gemstone mass between metric carats, points, grams, milligrams, and avoirdupois ounces without confusing carat weight with gold purity. Mbps to Gbps and GB/s Converter Convert megabits per second into gigabits per second, megabytes per second, gigabytes per second, and bits per second using decimal network units. KSI to MPa Pressure Converter Convert pressure in kilopounds per square inch into megapascals, psi, pascals, and gigapascals with explicit unit relationships. mmol/L to mg/dL Calculator Convert a selected laboratory analyte from mmol/L to mg/dL using its molecular weight, with a reverse-conversion check shown beside the answer. Drops to Milliliters Converter Convert a counted number of drops to milliliters, liters, and microliters using the measured drop volume for the actual dispenser. Decimal to Octal Converter Convert a safe-range decimal integer to prefixed octal and binary notation while preserving negative values and showing the digit count. Cents to Dollars Converter Convert a nonnegative number of US cents into dollars, whole dollars, and remaining cents without applying exchange rates. Days to Months Duration Converter Convert elapsed days to months and years using an average Gregorian, 30-day billing, or 365-day-year convention. Hours to Years Duration Converter Convert elapsed hours to years, 24-hour days, and minutes using an explicit hours-per-year convention. Euro Cents to Euros Converter Convert euro cents into euros, whole euros, and the remaining cent component without applying a foreign-exchange rate. Cubic Centimetres to US Fluid Ounces Converter Convert cubic centimetres into US fluid ounces, millilitres, US cups, and litres while keeping volume ounces separate from mass ounces. Numbers to Words Converter Convert whole numbers from zero through 999,999,999 into canonical English words, or parse those words back into a decimal integer. Pressure Unit Converter Convert pressure among pascals, kilopascals, megapascals, bar, standard atmospheres, pounds per square inch, and millimeters of mercury. Energy Unit Converter Convert joules, kilojoules, megajoules, watt-hours, kilowatt-hours, calories, kilocalories, and British thermal units. Power Unit Converter Convert watts, kilowatts, megawatts, mechanical horsepower, and British thermal units per hour. Force Unit Converter Convert newtons, kilonewtons, pounds-force, and kilogram-force through a shared SI base. Frequency Unit Converter Convert hertz, kilohertz, megahertz, gigahertz, and revolutions per minute using cycles per second as the base. Torque Unit Converter Convert newton-meters, kilonewton-meters, pound-feet, pound-inches, kilogram-force meters, and kilogram-force centimeters. Capacitance Unit Converter Convert capacitance values among farads and common SI-prefixed units. Decimal Degrees and DMS Converter Convert a signed decimal-degree coordinate to degrees-minutes-seconds or convert DMS back to decimal degrees. Density Unit Converter Convert density values among common SI and mass-volume units. Custom-Rate Currency Converter Convert an amount with a rate you supply instead of silently using stale or unverified live exchange data. Shoe Size Conversion Convert an approximate shoe size among US men's, US women's, UK, EU, and Japanese length systems.

Data Storage Converter Convert bits, bytes, decimal SI storage units, and binary IEC storage units without mixing GB and GiB. Number Base Converter Convert whole numbers between decimal, binary, octal, and hexadecimal. Download Time Estimator Transfer time from file size and connection speed, bits vs bytes kept straight. Password Strength (Entropy Bits) Guessing resistance of a random password from alphabet and length. IPv4 Subnet Calculator Calculate the network, mask, broadcast, address range, and usable hosts for an IPv4 address and CIDR prefix. IPv6 Subnet Calculator Calculate the canonical network prefix, address range, host bits, and exact address count for an IPv6 CIDR prefix. Battery Runtime Calculator Estimate battery runtime and stored energy from capacity, load current, and voltage. Camera Field of View Calculator Calculate a camera’s horizontal field of view from sensor width and focal length. Bandwidth-Delay Product Calculator Calculate the data in flight from network bandwidth and round-trip delay. Data Transfer Bandwidth Calculator Calculate average bandwidth from a data size and transfer duration. Integer Bit Shift Calculator Shift a signed integer left and right with exact text-preserving integer arithmetic. Camera Crop Factor Calculator Calculate crop factor and equivalent focal length from sensor diagonal and a reference sensor diagonal. Baud Rate and Bit Rate Calculator Convert symbol rate and bits per symbol into an ideal gross bit rate. Duty Cycle Calculator Calculate duty-cycle percentage and off-time from on-time and off-time in a repeating cycle. Caesar Cipher Shift Calculator Shift letters through the Latin alphabet by an entered amount while preserving case and nonletters. Unix Permission Mode Calculator Decode a three-digit Unix-style permission mode into owner, group, and other read/write/execute permissions. Beat-Delay Time Calculator Calculate beat-based delay time from tempo and a selected number of beats. Binary Addition Calculator Add two nonnegative binary integers with exact text-preserving output in binary and decimal forms. Depth of Field Calculator Estimate near focus, far focus, and depth of field from focal length, aperture, focus distance, and circle of confusion. Drone Flight Time Estimate Estimate usable drone flight time from battery voltage, capacity, average power draw, efficiency, and reserve percentage. Boost Converter Output Calculator Estimate ideal and efficiency-adjusted boost-converter output voltage and input current from duty cycle and load current. RC Cutoff Frequency Calculator Calculate the ideal first-order RC low-pass cutoff frequency from resistance and capacitance. Audio File Size Calculator Estimate uncompressed or simply compressed audio file size from duration, sample rate, bit depth, channels, and a compression ratio. Effective DPI Calculator Calculate effective mouse sensitivity in dots per inch from physical DPI and an in-game sensitivity multiplier. Frames to Timecode Calculator Convert a frame count and frame rate into hours, minutes, seconds, and remaining frames. Hamming Distance Calculator Count the positions at which two equal-length text strings differ. Two-Input Logic Gate Calculator Evaluate a selected two-input Boolean gate for binary inputs 0 and 1. Image File Size Estimate Estimate uncompressed image storage from pixel dimensions, bits per channel, channel count, and a compression ratio. Hamming Code Parity-Bit Count Calculator Calculate the minimum number of parity bits needed for a single-error-correcting Hamming-code layout. Pixels Per Inch Calculator Calculate horizontal and vertical pixel density from pixel dimensions and physical display or print dimensions. Luhn Check Digit Calculator Validate a digit string with the Luhn checksum and calculate the check digit for a payload. Ideal Buck Converter Calculator Estimate buck-converter output voltage, output power, and input current from input voltage, duty cycle, load current, and efficiency. Fan Affinity Laws Calculator Estimate how the flow, pressure rise, and shaft power of the same fan change when speed changes. Inductor Energy Calculator Calculate the magnetic energy stored in an ideal inductor from inductance and current. Solenoid Inductance Calculator Estimate the ideal self-inductance and stored energy of a long solenoid from its turns, area, length, permeability, and current. Shockley Diode Equation Calculator Estimate idealized diode current from saturation current, forward voltage, ideality factor, and temperature. Noise Figure from SNR Calculator Calculate noise figure and noise factor from input and output signal-to-noise ratios in decibels. Insertion Loss Calculator Calculate insertion loss in decibels and transmitted power percentage from input and output power. Amdahl's Law Parallel Speedup Calculator Estimate the speedup and remaining runtime of a workload when only a defined fraction can be accelerated. Binary Bytes to Text Converter Decode groups of eight binary digits as UTF-8 bytes and show the resulting text and byte representation. BPM Beat Duration Calculator Convert a tempo in beats per minute into beat length and the duration of a chosen number of beats. Data Transfer Time Calculator Estimate transfer time from data size, link rate, and an explicit overhead allowance. Engagement Rate Calculator Calculate an engagement percentage from recorded interactions and the audience denominator you choose. Hexadecimal Bytes to Text Converter Decode hexadecimal byte pairs as UTF-8 text while showing the byte count and decoded character count. Letters to Numbers A1Z26 Converter Map English letters to A1Z26 values and report the numeric sequence, sum, and average. Mirror Text Converter Reverse text by Unicode code point while reporting the number of code points and UTF-8 bytes. International Morse Code Converter Encode supported Latin letters, digits, and punctuation into International Morse code or decode it back. A1Z26 Numbers to Letters Converter Decode numbers from 1 through 26 into the corresponding English letters and show the total. MIDI Note Frequency Calculator Estimate the equal-tempered frequency of a MIDI note number relative to a chosen reference tuning. Pixels to Print Size Calculator Convert image pixel dimensions and a print resolution into physical size in inches and centimetres. Resolution Scaling Calculator Scale a pixel resolution while preserving its width-to-height ratio and estimate the resulting pixel count. Screen Size from Diagonal Calculator Estimate screen width, height, and area from diagonal size and an aspect ratio. Sentence Case Converter Normalize a short passage into sentence case and count its sentences and words. Streaming Bitrate Data Usage Calculator Estimate decimal storage and binary storage consumed by a stream at a given bitrate and duration. Unicode Subscript Text Generator Convert supported digits and symbols into Unicode subscript characters while reporting characters that could not be styled. Unicode Superscript Text Generator Convert supported digits and symbols into Unicode superscript characters while preserving unsupported text. Text to UTF-8 Hex Converter Encode text as UTF-8 bytes and display the exact hexadecimal byte sequence and byte count. Title Case Converter Convert a short passage to a readable title-style capitalization and report its word count. Battery Capacity and Usable Energy Calculator Translate a battery's nominal watt-hour rating into ampere-hours, usable energy, and an estimated load runtime with explicit efficiency and depth-of-discharge assumptions. LM317 Adjustable Regulator Output Calculator Estimate an LM317-style adjustable regulator output from the reference voltage, resistor divider, and adjust-pin current, then check available input headroom. Inverting and Non-Inverting Op-Amp Gain Calculator Calculate ideal closed-loop gain and output voltage for the two common resistor-feedback op-amp configurations. PCB Microstrip Impedance Estimate Estimate the characteristic impedance of a single-ended microstrip from dielectric constant, trace geometry, and reference-plane height. PCB Trace Current and Temperature-Rise Estimate Estimate current from copper cross-sectional area and an allowed temperature rise using a clearly labeled empirical starting relation. PCB Copper Trace Resistance and Loss Calculator Calculate a copper trace's resistance, voltage drop, and I²R loss from length, width, thickness, resistivity, temperature, and current. PCB Trace Width from Current Estimate Estimate the copper width required for a target current and allowed temperature rise using the inverse of a clearly labeled empirical area relation. First-Order RC Low-Pass Filter Calculate the cutoff frequency, time constant, gain, phase shift, and output amplitude of a simple RC low-pass filter. Parallel Resistor Network Find the equivalent resistance, source current, branch currents, and power for resistors connected in parallel across one voltage. Music Duration from Tempo and Bars Calculate the playing time of a musical passage from tempo, meter, and bar count. Musical Interval in Semitones Measure the ordered and unordered pitch distance between two notes, including interval class and frequency ratio. Music Scale Note Builder Build common major, minor, pentatonic, blues, and chromatic scales from a selected root note. Melody Note Transposer Transpose a space- or comma-separated note sequence by a chosen number of semitones. Major and Minor Key Signature Look up the conventional sharp or flat key signature for a major or minor tonic. Chord Note Builder Build the pitch classes and interval pattern for common triads and seventh chords. Chord Finder from Notes Match a set of three or four pitch classes to common triad or seventh-chord templates. Chord Inversion Note Order Reorder a common triad or seventh chord into root position or a selected inversion. Roman-Numeral Chord Progression Convert a simple Roman-numeral progression into diatonic chord names in a selected major or natural-minor key. Chord Transposer Transpose a chord root by a selected semitone interval while keeping its chord quality unchanged. Battery Size from Load and Runtime Estimate the battery energy and amp-hour capacity needed for a load, runtime, voltage, usable-depth limit, efficiency, and reserve. Propagation Delay Calculate one-way and round-trip signal travel time from path distance and propagation speed. RAM CAS Latency Convert a memory module's CAS latency and data rate into approximate true latency in nanoseconds. Video File Size from Bitrate Estimate encoded video file size from video bitrate, audio bitrate, duration, and container overhead. Upload Time from File Size and Speed Estimate the time to upload a file from its decimal size, connection rate, and effective transfer efficiency. 3D Render Time Estimate total animation render time from frame count, average frame time, parallel renderers, utilization, and overhead. Total Harmonic Distortion (THD) Calculate total harmonic distortion from fundamental and harmonic RMS amplitudes, including percent and dB views. Matched Pi Attenuator Calculate the two equal shunt resistors and center series resistor for a symmetric matched pi attenuator. Helmholtz Resonator Port Length Estimate the physical port length needed to tune a Helmholtz resonator to a target frequency with an explicit end correction. Camera Shutter Speed from Exposure Value Estimate shutter time from aperture, ISO, and a scene exposure value at ISO 100. Inverting Buck-Boost Duty Cycle Calculator Estimate the duty cycle needed for a negative output voltage in an ideal or efficiency-adjusted inverting buck-boost converter. Transformer Apparent-Power Sizing Calculator Estimate load VA, transformer input VA, primary and secondary currents, and an ideal turns ratio for an AC transformer scenario. Educational RSA Arithmetic Calculator Build a small textbook RSA key pair from two primes, calculate the private exponent, encrypt a numeric message, and decrypt it for learning. Vigenère Cipher Calculator Encrypt or decrypt a short A–Z message with a repeating Vigenère key while preserving spaces, digits, and punctuation. Uptime and Availability Calculator Calculate uptime, availability percentage, annualized downtime, and mean downtime per incident from a measured service window. IPv4 Address Converter Convert an IPv4 dotted-decimal address into its unsigned decimal, padded 32-bit binary, and hexadecimal representations. Floating-Point Bit Pattern Calculator Inspect the sign, exponent, fraction, hexadecimal bit pattern, and stored value for an IEEE-style binary32 or binary64 number. T9 Text and Keypad Converter Convert letters, spaces, and basic punctuation to repeated telephone-keypad digits, or decode separated T9 groups back to text. TV Size from Viewing Distance Calculator Estimate a display diagonal and width/height from viewing distance, target angular size, and aspect ratio without hiding a universal viewing recommendation. 3D Printing Material and Time Calculator Estimate material volume, filament mass, filament length, deposition time, and whole spools from an explicit 3D-print planning model. Projector Image Size Calculator Calculate projected image width, height, and diagonal from throw distance, throw ratio, and aspect ratio. Time-Lapse Frame and Capture-Time Calculator Calculate required frames, actual final clip duration, capture duration, and speed-up factor from time-lapse settings. Vocal Range Frequency Calculator Calculate semitone span, octave span, frequency ratio, geometric midpoint, and nearest equal-tempered note names from low and high frequencies. Speaker Box Net Volume Calculator Calculate gross internal enclosure volume and subtract entered driver, port, and bracing displacement to estimate usable acoustic volume. Crosstalk Voltage and Decibel Calculator Convert a coupled signal voltage relative to a source voltage into a crosstalk ratio, percentage, and voltage-based decibel value. ASCII Text and Code Converter Convert printable ASCII text to decimal, hexadecimal, and binary code values, or decode a short list of ASCII codes back into text. One's Complement Bit Pattern Calculator Invert a fixed-width binary word and interpret the result using one's-complement signed arithmetic, including the negative-zero case. Bitwise XOR Calculator Apply exclusive OR to two equal-length binary strings and report the result, decimal values, and differing-bit count. NOR Logic Gate Calculator Evaluate a two-input NOR gate, show the intermediate OR result, and identify the matching truth-table row. Parity Bit Calculator Choose even or odd parity for a binary data word and calculate the parity bit, transmitted codeword, and total one count. Series RLC Resonance and LC Filter Calculator Calculate the ideal resonant frequency, characteristic impedance, quality factor, bandwidth, and resonant current of a series RLC network. Timecode to Frame Number Calculator Convert an hours:minutes:seconds:frame position into a zero-based frame index and a one-based frame count for an integer-rate video timeline. Uncompressed Video Frame Size Calculator Estimate the raw size of one video frame and an uncompressed sequence from resolution, color depth, frame rate, and duration. Hash Format Identifier Inspect a hexadecimal digest, calculate its bit length, and return a transparent shortlist of common algorithms that share that length without claiming certainty. Aspect Ratio Calculator Calculate a width-to-height aspect ratio, simplify integer dimensions, scale to a target width or height, and find the diagonal. Blink-Free Group Photo Probability Calculator Estimate the chance that every person has eyes open in one group photo and the number of shots needed for a chosen success probability. Gematria Letter-Value Calculator Sum letter values for Hebrew and English text under explicitly named conventions, show the included characters, and keep non-letter symbols out of the total. Text to Binary Converter Convert a short text string to its UTF-8 binary and hexadecimal bytes, then verify the decoded text. Subnet Usable Hosts Usable hosts, network size, and mask for a CIDR prefix /1-/30. CIDR to Subnet Mask Dotted mask, wildcard, and address count from a CIDR prefix. Aspect-Ratio Fit Scaled dimensions and factor fitting a source rectangle inside a box. Color Contrast Ratio WCAG contrast ratio and conformance verdict for two hex colors. Logic Gate Evaluator Output and expression for one two-input Boolean gate. Uncompressed Media File Size Bitmap size from resolution, colour depth, frame count, and compression ratio. Big-O Operation Lookup Operation count for input size n under six common complexity classes. ASCII Code Lookup Decimal, hex, and HTML entity for one ASCII character plus its category. Unicode Code Point Inspector Reports the Unicode code point, hexadecimal notation, UTF-8 byte length, and UTF-16 code-unit length for one character. Crypto Mining Profitability (GPU and CPU) Compare daily revenue, electricity cost, and profit across seventeen mineable coins for one device or a whole mixed rig. NVIDIA GPU Mining Profitability Compare daily revenue, electricity cost, and profit across mineable coins for NVIDIA GeForce cards. AMD GPU Mining Profitability Compare daily revenue, electricity cost, and profit across mineable coins for AMD Radeon cards and Ryzen CPUs. ASIC Miner Profitability (Bitcoin, Litecoin, Kaspa and More) Compare daily revenue, electricity cost, and profit for ASIC miners: SHA-256, Scrypt, kHeavyHash, Blake2S and more. CPU Mining Profitability (Monero and CPU Coins) Estimate daily revenue, electricity cost, and profit for CPU mining with Ryzen and other processors. LLM VRAM Fit Estimator Estimate GPU memory for loading a language model from parameter count and quantization, and see which cards it fits. AI API Usage Cost Price an API workload from input/output token counts and per-million rates. Training Compute Estimator (6ND Rule) Estimate total FLOPs, PF-days, calendar time, and GPU-hours for a training run. Vector Database Size Estimator Estimate storage for an embedding index from vector count, dimensions, and precision. Random Password Generator Create a local random password with chosen character sets and an entropy estimate. Base64 Encode and Decode Encode UTF-8 text to standard padded Base64 or decode valid Base64 back to UTF-8. URL Encode and Decode Percent-encode a URI component or decode valid percent-encoded UTF-8 text. Roman Numeral Converter Convert canonical Roman numerals from I through MMMCMXCIX to integers and back.

Travel Fuel Cost Estimator Estimate fuel needed and trip cost from distance, consumption, and fuel price, with explicit units. Weekly Budget Planner Split a total budget evenly across a whole number of weeks to plan weekly spending. Tip and Bill Split Add a tip percentage and split the total evenly across diners. Recipe Scaler Scale any ingredient quantity between serving sizes. Unit Price Comparer Compare two pack prices by cost per unit weight or volume. Paint Estimator Gallons needed from paintable area, coats, and coverage per gallon. Running Pace and Speed Pace per kilometre or mile plus average speed from distance and time. Concrete Bags Estimator Bags of premix from slab volume and per-bag yield. Mulch and Soil Volume Cubic yards from bed area and depth, plus bag count. Fuel Cost Estimate Estimate fuel volume and cost from trip distance, fuel economy, and the price you enter. Tip, Tax, and Bill Split Calculator Calculate an entered tip and tax amount, total bill, and equal share per person. Audiobook Playback Time Calculator Calculate adjusted listening time and time saved when playback speed changes. Battery Charge Time Calculator Estimate charging time from battery capacity, charger current, and a charging-efficiency allowance. Flight Carbon Dioxide Estimate Estimate flight carbon dioxide from distance, fuel use, emission factor, and passenger count supplied by the user. Appliance Energy Cost Calculator Estimate energy use and cost from appliance power, operating time, days, and an entered electricity price. Classroom Space per Person Calculator Calculate floor area per person and total capacity from room dimensions and a chosen spacing allowance. Bathroom Mirror Width Calculator Calculate a maximum mirror width from vanity width and selected side clearances, plus mirror area from height. Balloon Arch Quantity Calculator Estimate balloon count from an arch length, center-to-center balloon spacing, and an optional planning allowance. Bath Versus Shower Water Calculator Compare weekly water use from showers and baths using explicit duration, flow, frequency, and bath-volume assumptions. Rectangular Bag Capacity Calculator Calculate internal volume and approximate litre capacity for a rectangular bag from dimensions and fill percentage. Antipode Coordinate Calculator Calculate the opposite point on Earth from a latitude and longitude using a spherical coordinate convention. Binge-Watching Time Calculator Calculate total viewing time and adjusted time at a selected playback speed from episode count and duration. Travel Cost per Distance Calculator Calculate fuel cost per kilometre and total trip fuel cost from fuel economy, fuel price, and distance. Cost per Minute Calculator Calculate cost per minute and total cost from a charge and the duration it covers. Aquarium Volume Calculator Calculate rectangular aquarium volume in litres and usable water volume from dimensions and a fill percentage. Cleaning Service Cost Calculator Estimate cleaning cost from area, price per area unit, visit count, and an optional supply allowance. Boat Speed and Travel Time Calculator Calculate average boat speed and travel time from distance and the other selected time or speed input. Bed Area and Linen Size Calculator Calculate rectangular bed area and a minimum mattress-covering size from bed length, width, and side allowance. Commute Time and Cost Calculator Estimate commute time and fuel cost from one-way distance, trips per week, speed, fuel economy, and fuel price. Bean Bag Filling Volume Calculator Estimate fill volume for an ellipsoid-like bean bag from its three overall dimensions and a selected fill fraction. Cubic-Metre Shipping Volume Calculator Calculate total shipment volume in cubic metres from rectangular package dimensions and quantity. Circle Skirt Fabric Calculator Estimate the inner radius, cut radius, and fabric area for a full-, half-, or quarter-circle skirt from waist, length, and allowance inputs. Clay Shrinkage Calculator Estimate dried or fired clay dimensions and volume change from wet dimensions and a stated linear shrinkage percentage. Cross-Stitch Fabric Size Calculator Convert stitch counts and fabric count into stitched dimensions, cut dimensions, and approximate fabric area with a visible margin. Curtain Panel Quantity Calculator Estimate finished panel count, total cut width, and fabric area from a window width, fullness ratio, panel width, and drop. Fuel Distance Calculator Estimate travel distance from fuel volume and vehicle consumption, with the result shown in kilometres, miles, and kilometres per litre. Carpool Cost Calculator Estimate shared trip distance, fuel use, total fuel cost, and equal cost per passenger from route, schedule, vehicle consumption, and fuel price. Rectangular Container Loading Calculator Estimate how many identical rectangular boxes fit in a rectangular container for one selected axis-aligned orientation, with axis counts and volume utilization. Pallet Packing Layout Calculator Compare two axis-aligned package orientations on a rectangular pallet and estimate per-layer capacity, footprint utilization, and total boxes across layers. TV Mounting Height Geometry Calculator Estimate a screen's width, height, top, bottom, center position, and viewing angle from diagonal size, aspect ratio, eye height, and viewing distance. Garbage Bag Size Planner Estimate the minimum flat width and length of a liner for a rectangular bin, then add visible fitting allowances before checking a product label. Picture Frame and Mat Size Calculator Calculate a mat outer size, frame outer size, visible artwork area, mat area, and frame perimeter from artwork and border measurements. Paper Thickness and Stack Height Calculator Infer sheet caliper from a measured paper stack and project the height, inches, and sheets-per-inch for another sheet count. Paper Sheet Mass and Ream Weight Calculator Calculate the mass of paper sheets and a 500-sheet ream from grammage, sheet dimensions, and quantity. Quilt Binding Strip Calculator Estimate binding length, whole strips, fabric cut width, and unused strip length from quilt dimensions and a visible joining allowance. Desk Height Fit Calculator Compare entered seated and standing elbow heights with task offsets and desk adjustment ranges without claiming one universal ergonomic height. Diaper Supply Planner Estimate disposable diaper units and packs for a stated number of babies, days, daily changes, buffer, and package size. Cordwood Volume Calculator Convert a rectangular stacked firewood pile into cubic feet, standard cord equivalents, and an entered purchase estimate. Helium Balloon Lift and Quantity Calculator Estimate the lift of one spherical helium balloon and the number needed for a payload after accounting for envelope mass and a visible planning margin. Meeting Cost Calculator Estimate the direct and loaded cost of a meeting from participant time, preparation time, a local hourly rate, and an explicit overhead percentage. Microwave Wattage Time Adjustment Calculator Scale a package or recipe heating time between two microwave power ratings while keeping the label-time assumption visible. Recessed Lighting Layout Calculator Estimate a regular recessed-light layout from room dimensions, a maximum spacing, edge margin, target illuminance, fixture lumens, and utilization assumptions. Shower Water and Heating Cost Calculator Estimate shower water volume, heating energy, water cost, and energy cost from flow, duration, temperatures, efficiency, and local prices. Wheel Offset and Backspacing Calculator Convert measured wheel backspacing and advertised width into the approximate wheel offset, centerline, overall width, and outboard spacing. Winch Line Pull Planning Calculator Estimate the line pull for moving a mass up a slope from grade, rolling resistance, line efficiency, and a visible safety factor. Crosswind and Headwind Component Calculator Resolve a wind speed into runway-relative crosswind and headwind or tailwind components using a selectable speed unit. Novel Writing Pace Calculator Plan the daily writing pace needed to reach a word-count goal and compare it with a steady entered pace over the remaining days. Lawn Mowing Cost Scenario Calculator Estimate productive mowing time, total visit time, per-visit cost, and seasonal cost from lawn area, mower productivity, user-entered rates, and visit count. Pet-Sitting Visit Cost Scenario Calculator Estimate a pet-sitting invoice from visits, visit duration, base rate, extra-pet fees, travel fees, and one-time charges without claiming a universal local rate. Dog Crate Internal Size Planner Plan minimum internal crate dimensions from a dog's measured body length, standing height, turning diameter, and explicit comfort clearances. Dog Harness Measurement Planner Turn a dog's chest girth, neck girth, and back length into transparent measurement targets with user-entered fit clearances before comparing a manufacturer's size chart. Rabbit Enclosure Space Check Calculator Compare a rabbit enclosure's available floor area and height with visitor-entered welfare baselines and an additional-rabbit allowance. Aquatic Turtle Tank Volume Planner Estimate minimum water volume, litres, and water depth from shell length, turtle count, and editable care-rule factors. Metric Ring Size Planner Convert a measured inner circumference into diameter, inches, and an ISO-style numeric ring-size reference without hiding regional sizing differences. Shoelace Length Planning Calculator Estimate lace length from eyelet pairs, eyelet spacing, across-shoe width, lacing style, and the total allowance needed for tying. Pool Salt Addition Planner Estimate the mass of salt needed to move a pool from a measured concentration to a target concentration using litres, cubic metres, or US gallons. Reading Speed and Study Pace Calculator Calculate words per minute from a timed reading sample and estimate words, pages, or minutes for a study session using that measured pace. Cash Weight Estimator Estimate the total mass, face value, and value density of repeated cash items from a user-entered count, denomination, and unit mass. Data Usage Budget Calculator Project total mobile or broadband data use from average daily usage, active days, an overhead allowance, and a plan limit in the selected data unit. Energy Use Intensity (EUI) Calculator Calculate a building’s annual energy use intensity from total annual energy, floor area, and globally usable energy and area units. Diamond Dimension Weight Estimator Estimate diamond carat weight from shape, dimensions, and an optional proportion adjustment, with clear distinction between planning weight and a laboratory measurement. Traffic Density and Flow Calculator Estimate vehicles per kilometre, per-lane density, flow per lane, and average spacing from a road segment observation. Tables Needed for Guests Calculator Calculate how many identical tables are needed for a guest count, plus seats provided, unused seats, and occupancy. NATO Phonetic Alphabet Encoder and Decoder Encode letters into the international NATO spelling alphabet or decode official code words back into text. Rat Cage Size and Space Check Calculator Compare a rat enclosure’s usable floor area and clear height with an entered welfare baseline for a specified number of rats. Amount in Words Calculator Turn a numeric amount into readable English currency words for supported international currencies, including major and minor units, with a clear warning for formal documents. Density-Based Freight Class Planning Calculator Estimate shipment density and the density-based NMFC planning class from package dimensions and total weight, with the classification boundary kept visible. Generator Wattage Planning Calculator Estimate a generator’s planning wattage and apparent-power requirement from continuous load, starting surge, overlap, reserve, and power factor. Hot-Tub Operating Cost Calculator Estimate hot-tub heating, pump, refill, recurring electricity, and first-fill costs from your equipment and local prices. Fabric Yardage and Cutting-Length Calculator Estimate fabric length for repeated rectangular pieces from piece dimensions, count, fabric width, and an explicit waste allowance. Blind and Shade Size Planner Plan an inside- or outside-mount blind size from opening measurements, depth, overlap, and mounting extensions without applying hidden manufacturer deductions. Pomodoro Focus Schedule Planner Plan focus sessions, short breaks, long-break placement, preparation, and wrap-up time with an explicit schedule rather than a fixed timer guess. D&D Money Conversion Calculator Convert copper, silver, electrum, gold, and platinum pieces into a common copper value and a normalized purse display. 5e Encounter Difficulty Calculator Estimate a fifth-edition 2014 encounter's adjusted XP and compare it with the party's easy, medium, hard, and deadly thresholds. Flag Size and Proportion Planner Plan a rectangular flag's fly length, face area, pole position, and remaining pole using a chosen hoist-to-fly ratio. Flooring Tiles Estimator Tiles needed for a floor area from tile size, plus a buy quantity with waste allowance. Sleep Cycle Wake-Up Time Wake-up time from a bedtime plus a whole number of 90-minute sleep cycles. Wallpaper Rolls Strips and rolls needed from wall size and roll size. Fence Boards Pickets needed for a run from board width and gap. Laundry Loads per Bottle Exact and whole wash loads from bottle size and dose. Pet Food Days Days and weeks one bag lasts at a fixed daily ration. Weekly Screen Time Weekly minutes and hours from average daily screen time. Formula Scoops Scoops of powdered formula from fluid ounces and scoops per ounce. Board Foot Calculate lumber volume in board feet from thickness, width, and length in customary dimensions. Drywall Panel Estimate Estimate the number of drywall panels from wall area, openings, panel size, and an entered waste allowance. Hollow Pipe Volume Calculate the internal volume of a straight hollow circular pipe from its diameters and length. Roof Pitch Calculate roof pitch percentage, slope angle, and rafter length from rise and horizontal run. Idling Fuel Consumption Estimate fuel used and fuel cost from an entered idle consumption rate and duration. Lighting Level Estimate average illuminance from lumens per fixture, fixture count, and illuminated area. Square Footage Calculator Calculate area for rectangles, circles, triangles, and trapezoids, with optional material cost. BTU Room Sizing Estimate Estimate room heating or cooling capacity with a visible area, ceiling, insulation, climate, and occupancy heuristic. Golf Handicap Differential Estimate Estimate a simplified 20-score handicap index from scores, course rating, slope, and PCC. Roofing Materials Estimate Estimate sloped roof area, roofing squares, and nominal bundles from a rectangular plan, pitch, and waste. Gravel and Aggregate Estimate Estimate gravel volume and mass from footprint, depth, waste, and bulk density. Bra Size Estimate Estimate a regional bra band and cup size from underbust and bust measurements. Electricity Use and Cost Calculator Estimate energy use and electricity cost from appliance power, hours, days, and an entered rate. Gas Mileage Calculator Calculate distance, fuel economy, fuel cost, and cost per distance from odometer and refueling readings. Stair Geometry Calculator Estimate riser count, actual riser height, tread count, total run, and stair angle from basic dimensions. Tire Size Comparison Calculate tire section height and overall diameter, then compare diameter and indicated-speed effects.