What are the limits of this calculator?

All dimensions use the same length unit. Inside-mount dimensions are reported at the exact opening size under this convention. Outside-mount overlap is applied on both sides. Outside top and bottom extensions are added to the opening height. The minimum depth is the product-specific requirement supplied by the visitor. Depth is checked for inside mount and is not used to approve an outside mount. Frame irregularity, obstructions, sill shape, hardware, and manufacturer deductions are not inferred. The narrowest width and appropriate height should come from repeated physical measurements. Coverage area is a planning value and not the fabric or slat area inside the headrail. Installation instructions and a product-specific measuring guide control the final order.

Blind and Shade Size Planner

Q: What do I need to use this calculator?

Enter Mount type, Window opening width, Window opening height, Available mounting depth, Product minimum depth, Outside overlap per side, Outside top extension, Outside bottom extension, then choose Calculate.

Plan an inside- or outside-mount blind size from opening measurements, depth, overlap, and mounting extensions without applying hidden manufacturer deductions.

Key facts

What it does: Plan an inside- or outside-mount blind size from opening measurements, depth, overlap, and mounting extensions without applying hidden manufacturer deductions.
Formula: Inside order width = opening width and inside order height = opening height under an exact-measurement convention. Outside order width = opening width + 2 × side overlap; outside order height = opening height + top extension + bottom extension. Inside depth margin = available depth − minimum product depth.
You enter: Mount type · Window opening width · Window opening height · Available mounting depth · Product minimum depth · Outside overlap per side · Outside top extension · Outside bottom extension
Worked example: The inside-mount planning size is 120 × 150 units with a 2-unit depth margin; no factory deduction is applied.

A clearer path to an answer

From your question to a useful result

This page keeps the calculation transparent: define the goal, enter the matching values, inspect the method, and decide what the result means in your situation.

Goal

Plan an inside- or outside-mount blind size from opening measurements, depth, overlap, and mounting extensions without applying hidden manufacturer deductions.

Inputs

Mount type · Window opening width · Window opening height · Available mounting depth · Product minimum depth · Outside overlap per side · Outside top extension · Outside bottom extension

Method

Inside order width = opening width and inside order height = opening height under an exact-measurement convention. Outside order width = opening width + 2 × side overlap; outside order height = opening height + top extension + bottom extension. Inside depth margin = available depth − minimum product depth.

Next step

Calculate, review the assumptions below, then compare a related tool when the decision needs more context.

Calculator usage statistics

Usage of this calculator and related tools

This section counts anonymous successful Calculate submissions, not unique visitors. Counts and top tools appear only when trusted aggregate data is available; country analysis is shown only under the same condition and reporting threshold.

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Context and background

Why everyday estimates stay transparent

Everyday tools turn a measured quantity, a rate, or a simple ratio into a practical estimate while leaving live prices, routes, and local rules to the visitor.

Practical calculators are small applied models. Their value is that a person can inspect an assumption, change it, and see how the decision changes without mistaking the result for a promise.

Research and review

How this guide was researched

Researched by Hassan ALRowaie, Founder and editorial researcher at WorldCalculate.

Last editorial review: September 16, 2026

This guide follows the live calculator's declared inputs, formula, worked example, assumptions, validation boundaries, and source-backed methodology. The review date describes editorial review of the calculator explanation; it is not a promise that external facts or rates remain current.

Read the WorldCalculate research and methodology policy

WorldCalculate visual showing distance, efficiency, power, energy, battery capacity, time, and playback speed estimates for Blind and Shade Size Planner — Everyday estimates become useful when distance, efficiency, power, energy, capacity, and time use matching units. An original everyday-planning visual separating travel distance, efficiency, fuel or electricity, battery capacity, time, and playback speed. WorldCalculate original artwork; watermark included.

A blind can be the wrong size even when the arithmetic is correct: mounting depth, frame irregularity, overlap, hardware, and product-specific deductions all matter. This planner separates the measurement convention from the final manufacturer order so visitors can prepare a clearer measurement record.

Small WorldCalculate visual connecting distance, efficiency, power, energy, battery, time, and playback speed for Blind and Shade Size Planner — State the unit and period first; the same number can mean something different under a different rate or horizon. Compact utility visual showing how common travel, energy, battery, and listening questions become estimates. WorldCalculate original artwork; watermark included.

Inside mount versus outside mount

Inside mount fits within the opening and outside mount extends over the opening or surrounding wall. Select the mount first because the same measured window produces different planning dimensions.

Inside-mount dimensions

Under this page’s convention, inside width and height are the entered opening measurements. No factory deduction is invented; product-specific ordering instructions may apply their own manufacturing allowance.

Outside-mount overlap

Outside width adds the chosen overlap on both sides. This lets a visitor model extra light-gap coverage or trim coverage while keeping the overlap assumption visible.

Height extensions

Outside height adds the selected top and bottom extensions. The top value can represent hardware clearance and the bottom value can represent a desired coverage point, but the correct values depend on the window and product.

Depth check

Inside mounting also needs enough recess depth for the specific headrail or shade. The displayed margin is available depth minus product minimum depth; a negative margin is a warning, not a recommendation to force the installation.

Worked example

For a 120-by-150 opening with 7 units of depth and a 5-unit product requirement, the inside planning size remains 120 by 150 and the depth margin is 2 units. An outside choice would add the selected overlap and extensions instead.

Measure more than once

Openings can vary from top to bottom and side to side. Record repeated measurements and use the product guide’s rule for selecting the narrowest width or appropriate height rather than assuming the frame is square.

Obstructions and hardware

Handles, latches, trim, sills, brackets, and headrails can change whether an inside mount is practical. The calculator cannot see those obstructions, so the visitor must add them to the final review.

Common input mistakes

Do not mix width and height, add outside overlap only once, or use a generic depth number in place of the product’s actual minimum. Keep the unit and mount type beside the measurement record.

Limitations and FAQs

This page prepares a transparent size scenario; it does not choose a blind, certify fit, calculate installation hardware, or override a manufacturer’s measuring and deduction instructions.