Door and Window Area Calculator
Calculate total door area, window area, combined opening area, opening count, and perimeter for construction, painting, drywall, wallpaper, or insulation deductions.
Results
This calculator treats doors and windows as simple rectangles. For arched windows, sidelights, bay windows, divided panels, trim, casing, or unusual shapes, calculate each section separately and add the extra opening area.
Use this Door and Window Area Calculator to estimate the total area of doors, windows, and other wall openings. The result can be used when estimating paint, drywall, wallpaper, insulation, or other wall materials.
Calculation Method
Single door area = door width × door height
Total door area = single door area × number of doors
Single window area = window width × window height
Total window area = single window area × number of windows
Total opening area = door area + window area + other opening area
For rectangular openings:
Perimeter = 2 × (width + height)
Example
Suppose you have one door measuring 3 ft × 7 ft and four windows measuring 4 ft × 5 ft.
Door area = 3 × 7 = 21 ft²
Window area = 4 × 5 × 4 = 80 ft²
Total opening area = 21 + 80 = 101 ft²
The combined door and window area is 101 square feet.
Important Notes
- Use the same measurement units for width and height.
- The calculator assumes rectangular doors and windows.
- Calculate different opening sizes separately and add the results.
- Arched, circular, bay, or irregular openings may require separate area calculations.
- Confirm whether your project requires rough-opening, frame, or finished-opening measurements.