Paint Calculator
Estimate paint for the walls of a rectangular room, optionally including the ceiling and subtracting doors and windows.
Results
Paintable area
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Area including coats
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Paint required
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Paint coverage varies by product, surface texture and application method, so use the manufacturer’s coverage figure when possible.
How it works
The calculator finds wall area from the room perimeter and wall height, optionally adds the ceiling, subtracts openings, multiplies by the number of coats, then divides by the selected coverage rate.
paint = paintable area × coats ÷ coverage rateWorked example
For a 12 ft × 10 ft room with 8 ft walls, no openings and two coats at 350 ft²/gal, the estimate is about 2.01 US gal.
Assumptions
- The room is rectangular and all walls use the same height.
- Coverage rate applies to one coat over the entered surface.
Limitations
- Highly porous, textured or previously unpainted surfaces may need more paint than the nominal coverage rate suggests.