calcs.homes
calcs.homes
Enter the room's footprint, the wall height, and the doors and windows to skip, and this calculator returns the gross and net wall square footage for paint, wallpaper, or paneling.
Estimate only — assumes four straight walls; bays, soffits, and vaulted ceilings need separate takeoffs.
Add the length of all four walls — two times length plus two times width — and multiply by the wall height for the gross wall area. Then subtract the openings: a standard interior door is about 21 sq ft and an average window about 15 sq ft. What is left is the net area you actually coat or cover.
Whether to subtract openings depends on the job. For paint, small rooms are often figured gross for a built-in margin; large glass walls should always be deducted. For wallpaper and paneling, subtract the openings but keep the offcuts — they rarely fit anywhere else, so your real yield is lower than the net number suggests.
Multiply the room perimeter (2 × length + 2 × width) by the wall height, then subtract about 21 sq ft per door and 15 sq ft per window.
For paint on a small room it is optional and adds margin. For large openings, wallpaper, or paneling, always subtract them.
This tool uses 21 sq ft for an interior door (about 3 × 6.7 ft) and 15 sq ft for an average window. Adjust the counts if your openings are much larger.