How Much Paint for a Room? (12x12, 10x10 and More)
How many gallons of paint you need for common room sizes, with and without the ceiling, plus a quick way to calculate any room.
For a standard room with 8 ft ceilings, you need about 1 gallon per coat for every 350–400 sq ft of wall. In practice, most bedrooms take about 2 gallons for two coats on the walls.
Here are the numbers for common room sizes, assuming one door, one window, 8 ft walls and 350 sq ft per gallon.
Paint needed by room size (two coats)
| Room | Wall area | Walls only | Ceiling (2 coats) |
|---|---|---|---|
| 10 × 10 ft | ~284 sq ft | ~1.6 gal | +0.6 gal |
| 12 × 12 ft | ~348 sq ft | ~2.0 gal | +0.8 gal |
| 12 × 14 ft | ~380 sq ft | ~2.2 gal | +1.0 gal |
| 15 × 20 ft | ~524 sq ft | ~3.0 gal | +1.7 gal |
Round up to whole gallons or add a quart, and keep a little for touch-ups.
How to calculate any room
- Add the length and width, double it, and multiply by the wall height.
- Subtract 21 sq ft per door and 15 sq ft per window.
- Multiply by the number of coats and divide by the coverage on the can.
The paint calculator does this for you, including the ceiling, several identical rooms and the cans to buy.
Don't forget
- Trim and doors usually take a separate quart of semi-gloss.
- Vaulted ceilings add wall area. Measure the tallest wall at its average height.
- Dark colors may need a third coat or a tinted primer.