Window Blind Size Calculator

Window Blind Size Calculator: equations, variables, units and worked solution

The window blind size calculator calculates Inside-mount order width, Inside-mount order height, Outside-mount order width, Outside-mount order height, Outside blind area from Opening width, Opening height, Inside-mount width deduction, Inside-mount height deduction, Outside overlap per side, Outside top overlap, Outside bottom overlap. It does not hide the arithmetic: the result panel shows the governing formula, canonical-unit conversion, numeric substitution, unrounded evaluation and final rounded answer for every output.

Variables and measurement units

For the Window Blind Size Calculator, Opening width, Opening height, and Inside-mount width deduction are normalized to in, in, and in before max(0,openingWidth-insideWidthDeduction) is evaluated. The unrounded value used for max(0,openingWidth-insideWidthDeduction) and Inside-mount order width is retained internally; formatting is applied only to the result cards.

Formula model

Inside-mount width subtracts the manufacturer deduction; outside-mount dimensions add the selected side, top and bottom overlap allowances.

Formula-based worked derivation

1. Inside-mount order width
   1. Formula: Inside-mount order width = max(0,openingWidth-insideWidthDeduction)
   2. Default substitution: Inside-mount order width = max(0,(36)-(0.25))
   3. Unrounded evaluation: 35.75 in
   4. Displayed answer: 35.75 in
2. Inside-mount order height
   1. Formula: Inside-mount order height = max(0,openingHeight-insideHeightDeduction)
   2. Default substitution: Inside-mount order height = max(0,(60)-(0))
   3. Unrounded evaluation: 60 in
   4. Displayed answer: 60 in
3. Outside-mount order width
   1. Formula: Outside-mount order width = openingWidth+2 × sideOverlap
   2. Default substitution: Outside-mount order width = (36)+2 × (1.5)
   3. Unrounded evaluation: 39 in
   4. Displayed answer: 39 in
4. Outside-mount order height
   1. Formula: Outside-mount order height = openingHeight+topOverlap+bottomOverlap
   2. Default substitution: Outside-mount order height = (60)+(2)+(1.5)
   3. Unrounded evaluation: 63.5 in
   4. Displayed answer: 63.5 in
5. Outside blind area
   1. Formula: Outside blind area = (openingWidth+2 × sideOverlap) × (openingHeight+topOverlap+bottomOverlap) ÷ 144
   2. Default substitution: Outside blind area = ((36)+2 × (1.5)) × ((60)+(2)+(1.5)) ÷ 144
   3. Unrounded evaluation: 17.1979166667 ft²
   4. Displayed answer: 17.2 ft²

In the Window Blind Size Calculator, changing Opening width, Opening height, and Inside-mount width deduction rebuilds the numeric substitution for max(0,openingWidth-insideWidthDeduction). The engine converts selected measurements to in, in, and in, retains unrounded values, and, when reverse solving is available, inserts the solved variable back into the same equation to verify max(0,openingWidth-insideWidthDeduction) and Inside-mount order width with a numerical residual.

Input and output interpretation

Use measured or documented values for Opening width, Opening height, Inside-mount width deduction, Inside-mount height deduction, Outside overlap per side, Outside top overlap, Outside bottom overlap. The calculated outputs are Inside-mount order width, Inside-mount order height, Outside-mount order width, Outside-mount order height, Outside blind area. Check each intermediate line before relying on the final value; an implausible intermediate quantity usually identifies a unit, range or assumption error.

Algorithm and verification

The Window Blind Size Calculator uses its own `window-blind-size` JavaScript engine to calculate max(0,openingWidth-insideWidthDeduction) and Inside-mount order width from Opening width, Opening height, and Inside-mount width deduction with max(0,openingWidth-insideWidthDeduction). Calculator-owned boundary and mode tests check that workflow; an external frozen-reference oracle checks the numeric outputs, and physical source mutation testing confirms that a changed `window-blind-size` engine is rejected.

Visual interpretation

In the Window Blind Size Calculator, this guidance applies to Opening width, Opening height, and Inside-mount width deduction and the reported max(0,openingWidth-insideWidthDeduction) and Inside-mount order width. The `window-blind-size` workflow evaluates max(0,openingWidth-insideWidthDeduction) in in, in, and in; Measure the opening in multiple places and follow the selected manufacturer’s exact deduction and minimum-depth rules before ordering a custom blind.. Verification context: 106127.

Dimensional formula audit

The window blind size calculator normalizes openingWidth (Opening width, in), openingHeight (Opening height, in), insideWidthDeduction (Inside-mount width deduction, in), insideHeightDeduction (Inside-mount height deduction, in), sideOverlap (Outside overlap per side, in), topOverlap (Outside top overlap, in), bottomOverlap (Outside bottom overlap, in) before evaluating the equations. Its reported quantities are Inside-mount order width in in, Inside-mount order height in in, Outside-mount order width in in, Outside-mount order height in in, Outside blind area in ft². This separation matters because a numerical value without its measurement dimension can produce a plausible-looking but physically or financially incorrect answer. Conversion factors are applied before substitution, and output conversion occurs only after the canonical result has been calculated at full precision.

• Inside-mount order width = max(0,openingWidth-insideWidthDeduction)
• Inside-mount order height = max(0,openingHeight-insideHeightDeduction)
• Outside-mount order width = openingWidth+2 × sideOverlap
• Outside-mount order height = openingHeight+topOverlap+bottomOverlap
• Outside blind area = (openingWidth+2 × sideOverlap) × (openingHeight+topOverlap+bottomOverlap) ÷ 144

Formula sensitivity and boundary verification

To verify the window blind size calculator, hold all other inputs fixed and change openingWidth within its permitted range. The live substitution line shows exactly where that value enters the equation for Inside-mount order width. Repeat the check with openingHeight. The result must follow the displayed algebra, remain finite, and retain the stated output unit. At minimum and maximum boundaries, the validator rejects undefined domains, impossible denominators and nonphysical values rather than silently returning a number.

Manual reproduction of the result

For an independent hand check, first convert every selected unit to the canonical units shown in the variable table. Next copy the governing equation, replace each symbol with the canonical value shown in the live derivation, and calculate the intermediate expression without early rounding. Finally round only once to the displayed precision and compare both the numerical value and unit with the calculator card. This process makes the window blind size calculator reproducible instead of relying on an unexplained result.

Limitations

Measure the opening in multiple places and follow the selected manufacturer’s exact deduction and minimum-depth rules before ordering a custom blind.