Wall Area for Paint Calculator

Perimeter × ceiling height − doors and windows = paintable area.

Inputs

Result

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How to use this calculator

  • Measure room perimeter (sum all wall lengths).
  • Enter ceiling height.
  • Count doors and windows.

About this calculator

Wall area for paint is room perimeter × ceiling height, minus the area of doors and windows you don't plan to paint. Standard openings: door = 21 ft² (3×7); window = 12 ft² average (varies). For exact projects, measure individual openings.

Frequently asked

Why subtract doors and windows?+
Don't need to paint glass or door surfaces — those are usually a different finish. Subtracting gives paintable wall area.
Standard door size?+
~3×7 ft = 21 ft². Slight variation: 30" or 36" wide × 80" tall.
What about closets?+
Add closet wall area if you're painting them. Otherwise just exclude.
Vaulted ceilings?+
Compute the average height (assuming triangular: peak height + low height / 2) for the gross calc. Or measure each wall separately.
Plus ceiling?+
Use ceiling-area separately if also painting overhead.

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Gallons needed — enter the wall area directly OR room dimensions (calculator subtracts doors/windows).
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Square Footage Calculator (Rectangular)
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Sheets needed = wall area / sheet area (32 ft² for 4×8, 48 ft² for 4×12).
Floor Area Calculator
L × W = floor area in ft². For flooring orders, multiply by 1.10 (10% waste).

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