You'll need about
2.50
gallons of paint
432
sq ft wall area
2
coats
2.5
gallons exact
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How this is calculated
2 × (length + width) × height = wall area · wall area × coats ÷ 350 sq ft per gallon = gallons. The estimate does not subtract doors and windows, so it errs slightly high — which is what you want, since running out mid-wall means a visible seam.
This is a planning estimate — always confirm against your supplier and the specifics of the job before ordering.
Paint calculator: FAQ
How much paint do I need for a room?
Figure the wall area — two times length plus width, times ceiling height — then divide by 350 (the square feet a gallon covers) and multiply by the number of coats. A 12×12 room with 9 ft ceilings needs about two gallons for two coats.
How much does a gallon of paint cover?
About 350–400 square feet per coat on primed, smooth walls. Rough or porous surfaces cover less. This calculator uses 350 to stay on the safe side.
Do I need one coat or two?
Two coats is standard for even color and durability, especially over a different color or fresh primer. This calculator defaults to two.
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