How much paint do you need for a room?
For most bedrooms and living rooms, two coats of wall paint take two or three gallons. The exact amount depends on the wall area, doors and windows, the number of coats and the paint's coverage.
Quick reference
Assumes 8 ft walls, one door, two windows, two coats and 350 sq ft per gallon. Ceilings are extra.
| Room | Wall area to paint | Two coats | Buy |
|---|---|---|---|
| 10 × 10 ft | 270 sq ft | 1.5 gallons | 2 gallons |
| 12 × 12 ft | 334 sq ft | 1.9 gallons | 2 gallons |
| 12 × 14 ft | 366 sq ft | 2.1 gallons | 2 gallons + 1 quart |
| 15 × 20 ft | 510 sq ft | 2.9 gallons | 3 gallons |
Measure your walls
- Add the lengths of all walls to get the perimeter. A 12 × 14 room has 12 + 14 + 12 + 14 = 52 ft.
- Multiply by the ceiling height: 52 × 8 = 416 sq ft.
- Subtract about 20 sq ft per door and 15 sq ft per window.
- Multiply by the number of coats and divide by the coverage on the can.
One coat or two?
Two coats give even colour and better durability, and are standard for a colour change. A single coat can be enough when repainting the same colour on a clean wall. Dark-to-light changes, fresh drywall and patched areas often need primer first.
Ceilings and trim
A 12 × 12 ceiling is 144 sq ft, under half a gallon per coat. Trim and doors use far less paint, usually a quart for a room.
Use the paint calculator for your exact measurements.
Reviewed October 2026 · How we build our calculators · Report an issue