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Door & Window Calculators

Window to Wall Ratio Calculator

Window-to-wall ratio for daylight and energy compliance, with the daylight factor estimate.

Enter values

Results update as you type.

Result

Window to wall ratio

20 %

Window to floor ratio
48 %
Daylight assessment
Very bright — consider solar gain and glare
Energy assessment
Low glazing — efficient but may feel dark
Opaque wall area
48 m²

About the Window to Wall Ratio Calculator

Window-to-wall ratio for daylight and energy compliance, with the daylight factor estimate.

Also known as: wwr calculator, glazing ratio, daylight ratio, window percentage of wall.

How to use this calculator

  1. Enter total wall area, total window area, floor area.
  2. The result updates instantly as you type — press Calculate (or Enter) at any time.
  3. Review the breakdown shown under the main result.
  4. Use Copy result or Share to save the answer or send a link with your inputs.

Formula

WWR = window area ÷ gross wall area × 100

Worked example

Using the values pre-filled in the calculator above:

  • Total wall area = 60 m²
  • Total window area = 12 m²
  • Floor area = 25 m²

the calculator returns:

  • Window to wall ratio: 20 %
  • Window to floor ratio: 48 %
  • Daylight assessment: Very bright — consider solar gain and glare
  • Energy assessment: Low glazing — efficient but may feel dark