Wall Square Footage Calculator (minus Doors and Windows)
How to calculate square feet of a wall: multiply its length by its height and take off the doors and windows. Enter a room's sizes and counts and get the net wall area, with each wall worked out in the table below.
A ready-made setup of the Paint Calculator.
Estimates for planning, not professional advice. Read the full notice.
Example: a twelve by fourteen foot room
365 ft²
- Walls before openings 416 ft²
- Doors and windows 51 ft²
Estimate for planning, from what you entered and the product data shown. Check product labels and your supplier before you buy.
Your project
Enter a size to see your total.
Each product is rounded up once for the whole project, so the total can be less than the items bought alone added together. A line counted from a cut layout (sheets, boards or tiles laid out piece by piece) is counted for each item and added.
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| Item | Size | Buy |
|---|
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Worked example: a twelve by fourteen foot room
Show the working
- Wall area before openings: the distance around the room times the wall height 52 ft × 8 ft = 416 ft²
- Take off the door and the two windows 416 ft² − 21 ft² − 15 ft² − 15 ft² = 365 ft²
Assumptions
The figures behind the example. Sourced figures link to their source below; a default is a starting value to check against your label or supplier.
| Assumption | Value | Details and changes |
|---|---|---|
| Door opening (width by height) | 36 in × 84 in | |
| Default A common size, not sourced here. Check your label or supplier. | ||
| Window opening (width by height) | 36 in × 60 in | |
| Default A common size, not sourced here. Check your label or supplier. | ||
Feet and inches, like 12' 6"
The example room, wall by wall
Length, gross area, openings and net area of each wall of the example room
| Wall | Length | Gross area | Doors and windows | Net area |
|---|---|---|---|---|
| Wall 1 | 12 ft | 96 ft² | 21 ft² | 75 ft² |
| Wall 2 | 14 ft | 112 ft² | 15 ft² | 97 ft² |
| Wall 3 | 12 ft | 96 ft² | 15 ft² | 81 ft² |
| Wall 4 | 14 ft | 112 ft² | 0 ft² | 112 ft² |
The door goes on the first wall and the windows on the next two, only to show how a wall is worked. The room total does not depend on which wall holds an opening.
Questions
How do you calculate the square footage of a wall?
Multiply the wall's width by its height, then take off the area of each door and window. For a room, add up the walls, or multiply the distance around the room by the height.
Do I subtract windows from the wall area?
For paint, wallpaper or drywall you usually take off openings. The Doors and windows choice does that at the door and window sizes in the assumptions, which you can change, or counts the walls whole.