Home projects
Estimate paint without guessing.
Measure a room or wall, subtract doors and windows, then account for coats, product coverage, and a practical waste allowance.
Your estimate
Paint needs will appear here.
Enter the room or wall dimensions to begin.
Your estimate
Calculated paint
Whole units to buy
Paintable area
Area with coats and waste
Why coverage is an estimate
Paintable wall area is the wall surface minus openings. Multiple coats multiply that area, and a waste allowance helps cover roller loading, touch-ups, and small measurement differences.
Texture, porosity, application method, color changes, and the specific product can all change coverage. Use the coverage printed on the paint label when it differs from the default.
Reference: Sherwin-Williams paint guidance says a gallon typically covers about 350 to 400 square feet, depending on the surface and desired coverage.
This calculator is a planning estimate. Confirm container sizes, product coverage, surface preparation, and application instructions before purchasing.
Worked example and assumptions
A 12-by-8-foot wall has 96 square feet before subtracting doors or windows. Two coats and a waste allowance increase the area the product must cover, so the final amount is not simply the wall’s first measurement divided by the label coverage.
Assumptions: dimensions are entered in one unit system, openings are measured separately, and the coverage value matches the product. Texture, porosity, application method, color changes, and surface preparation can change the result.
Method and reference link reviewed September 29, 2026.
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