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Paint coverage calculator
Most interior paints cover about 350 sq ft per gallon per coat. Enter a room or a known wall area, subtract openings, and round up before you buy.
Results
Enter values to see results.
How this calculator works
Wall area = 2 x (length + width) x height, minus 21 sq ft per door and 15 sq ft per window. Optional ceiling adds length x width. Gallons = (area x coats) / coverage, then rounded up to a whole gallon for purchasing.
Texture, primer, dark colors, and cheap rollers all change real coverage. Check the can and buy a little extra from the same lot.