Calculate window area in square feet or square meters from width and height, for one window or several, with an option for visible glass area.

Optional settings

Related Calculators

Window Area Formula

The following formula gives full rectangular area in square feet when width and height are entered in inches. For visible glass, subtract twice the uniform frame width from each outside dimension before multiplying; a zero frame width is allowed.

WA = WL / 12 × WH / 12

Variables:

  • WA is the Window Area (ft^2)
  • WL is the window length (in) 
  • WH is the window height (in) 

To calculate full window area, multiply outside width by outside height in consistent units. Visible glass area is (width – 2 * frame) * (height – 2 * frame), with both clear dimensions greater than zero. This estimate excludes mullions, glazing bars and irregular shapes. Full opening area alone does not determine visible glass area. Total area multiplies the selected per-window area by a whole-number window count.

How to Calculate Window Area?

For the area modes, select the area basis and enter the dimensions. For a reverse solve, choose width or height and enter the known area of one window and the other outside dimension. With a frame deduction, outside width = area / (height – 2 * frame) + 2 * frame; interchange width and height for the other solve.

  1. First, determine the window length (in). 
  2. Next, determine the window height (in). 
  3. Next, gather the formula from above: WA = WL /12 * WH/12.
  4. Finally, calculate the Window Area.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

window length (in) = 25

window height (in) = 36

WA = WL /12 * WH/12 = 25/12 * 36/12 = 6.25 ft²