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Wall Area Calculator
Calculate total wall area from room length, width, and wall height, with optional door and window deductions.
Enter your dimensions
Current unit: feet. The estimate updates automatically in your browser.
Enter the room length.
Enter the room width.
Enter the wall height from floor to ceiling.
Optional. Enter total door area to subtract.
Optional. Enter total window area to subtract.
Estimated result
Net wall area
Enter your inputs
Your estimate will appear here automatically once the required inputs are valid.
Guide
How to use this estimate
How the wall area calculator works
This calculator estimates the area of the four walls in a rectangular room. It adds the room length and width, doubles that perimeter, multiplies by wall height, and then subtracts optional door and window areas.
The result is the net wall area you can use when planning paint, wallpaper, wall panels, or other wall coverings.
What to measure
Measure the room length, room width, and wall height. Use the same unit system for all three measurements.
If you know the total door and window area, enter those deductions. If you do not know them, leave the optional fields blank and treat the result as a gross wall-area estimate.
Example wall area calculation
- Room length: 12 feet
- Room width: 10 feet
- Wall height: 9 feet
- Gross wall area: 2 × (12 + 10) × 9 = 396 square feet
- Door and window deductions: 36 square feet
Estimated net wall area: 360 square feet.
Quick reference
| Item | Value | Note |
|---|---|---|
| Gross wall area | 2 × (length + width) × height | Works for a simple rectangular room. |
| Net wall area | Gross wall area - deductions | Subtract doors, windows, or openings when known. |
| Best use | Paint, wallpaper, wall panels | Use this before material-specific calculators. |
Common mistakes to avoid
- Forgetting to include wall height.
- Subtracting doors or windows twice.
- Using floor area as wall area. These are different measurements.
Frequently asked questions
Should I subtract doors and windows?
Yes, if you want a net wall-area estimate. If you want a safer buying estimate, you can leave deductions out or subtract only large openings.
Can this handle non-rectangular rooms?
For irregular rooms, calculate each wall separately or split the room into simpler sections.
Is this enough for paint planning?
It gives the wall area. For paint quantity, use the Paint Calculator with wall area, coats, coverage, and waste allowance.