Wall Area Calculator
This wall area calculator finds the net wall area of a room after removing doors and windows. Enter the room length, width, and wall height, plus the number and size of doors and windows, and the wall area calculator returns the net wall square footage in square metres and square feet, with the gross area and openings.
Results
The Wall Area Calculator is part of our Floor & Wall collection. Browse more floor & wall to size, convert, and check your work alongside this tool.
What the wall area calculator shows
A room's wall area is its perimeter times its height, less the space taken by doors and windows. The wall area calculator does that in one step and shows the gross area, the openings, and the net area. The net figure is the starting point for estimating any wall finish.
Calculate wall surface area
Square metres convert to square feet by multiplying by 10.764. For a single wall, its area is just its width times its height.
Wall area calculator example
A 5 m by 4 m room with 2.5 m walls, one 1.9 m² door, and two 1.5 m² windows:
That net area is what a wall finish has to cover.
How to use the wall square footage calculator
Enter the room length, width, and wall height, then the number of doors and windows and the area of each. The wall square footage calculator returns the net wall area in square metres and square feet, the gross area, and the total openings. A standard door is about 1.9 m² (0.9 by 2.1 m).
Reading the square footage of walls calculator result
Use the net area for finishes that skip openings. Some estimators deduct only large openings and leave small windows in as a waste margin. Rooms with sloped ceilings, alcoves, or bays need those extra wall sections added separately.
When to calculate area of a wall
- Measuring a room before ordering any wall finish
- Finding the square footage of a wall for a quote
- Comparing rooms by wall space
- Converting wall area between m² and sq ft
Common wall area calculator mistakes
- Forgetting alcoves and closets.
- Measuring height to the cornice instead of the ceiling.
- Mixing metres and feet.
Tips for accurate results
- Measure every wall, not just two.
- Note door and window sizes as you go.
- Keep units consistent throughout.
Square footage of a wall with odd shapes
For a gable wall, add the rectangle below the roof line to the triangle above it, which is half its base times its height. For a wall under a sloped ceiling, average the low and high heights and multiply by the width. Add these sections to the rectangular walls before subtracting openings. Patterned finishes need extra allowance for matching, which the wallpaper calculator includes.
Room wall area calculator vs single wall
To measure one feature wall, set the width to that wall and enter zero for the other side, or simply multiply its width by its height.
Wall square meter calculator reference (1 door, 1 window)
| Room | Height | Net area | Net sq ft |
|---|---|---|---|
| 3 × 3 m | 2.4 m | 25.4 m² | 273.4 |
| 4 × 3 m | 2.5 m | 31.6 m² | 340.1 |
| 5 × 4 m | 2.5 m | 41.6 m² | 447.8 |
| 6 × 5 m | 2.7 m | 56.0 m² | 602.8 |
Wall Area Calculator FAQ
How do I calculate wall area?
Multiply the room perimeter by the wall height, then subtract doors and windows.
How big is a standard door?
About 0.9 by 2.1 m, or 1.9 m², in many homes.
Should I subtract windows?
Yes for large windows; small ones are often left in as a margin.
How do I convert square metres to square feet?
Multiply by 10.764.