Dates, time, and planning

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.

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.

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.

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.

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.