Find the paintable wall area of a room. Enter the room size, ceiling height, and how many doors and windows to subtract their openings.
Wall Area (net)
— sq ft
Paintable wall area.Usage Tip
For wallpaper, keep the gross area and let the pattern repeat cover the openings as waste. The deductions here assume you skip painting behind the doors and windows.
THE MATH
Gross wall = 2 × (Length + Width) × Height
Openings = doors × 21 + windows × 15 sq ft
Net wall = Gross − openings
Openings = doors × 21 + windows × 15 sq ft
Net wall = Gross − openings
Wall area is the room perimeter times ceiling height — the surface you paint, wallpaper, or drywall, which is different from floor area.
Standard deductions assume a 3 × 7 ft door (21 sq ft) and a 3 × 5 ft window (15 sq ft); adjust the counts if yours are larger or smaller.
Standard deductions assume a 3 × 7 ft door (21 sq ft) and a 3 × 5 ft window (15 sq ft); adjust the counts if yours are larger or smaller.
Run this once per room and add the rooms together; ceiling height and openings vary room to room.
For paint, take the net wall area to the paint-coverage calculator for gallons — one gallon covers roughly 350 to 400 sq ft per coat.
Closets, soffits, and half-walls change the number; measure odd walls separately and add them.
For paint, take the net wall area to the paint-coverage calculator for gallons — one gallon covers roughly 350 to 400 sq ft per coat.
Closets, soffits, and half-walls change the number; measure odd walls separately and add them.