Work out how many gallons of paint you need from wall area, coats and coverage — with a quick way to estimate your wall area.
| Input | Result |
|---|---|
| 350 sq ft, 2 coats, 350/gal | 2 gallons |
| 282 sq ft, 2 coats, 350/gal | 2 gallons (1.61 exact) |
| 600 sq ft, 1 coat, 400/gal | 2 gallons (1.50 exact) |
Perimeter × wall height, minus doors and windows. A 12×10 ft room with 8 ft ceilings: (12+12+10+10)×8 = 352 sq ft, minus about 2 doors (40) and 2 windows (30) → ≈282 sq ft of paintable wall.
Almost always yes — one coat rarely hides the old color evenly. Dark-to-light changes may need a tinted primer plus two coats.
Paint is sold by the gallon and color batches vary slightly — buying the rounded-up amount ensures one uniform batch. Leftover paint is useful for touch-ups.
Ceilings use the same math: length × width of the room, one coat of ceiling paint usually suffices. Add it to your wall area separately.