How much paint do I need for a room?
Short answer
A 12 × 12 ft room with 8-foot walls, one door and two windows has about 334 square feet of wall. Two coats at 350 square feet per gallon take just under 2 gallons. Painting the ceiling too adds about another gallon.
Work it out for your numbers
Paint needed
1.91 gallons
- Cans to buy
- 2 1-gallon cans
- Paintable area
- 334 sq ft per coat
Paint by room size
| Room (8 ft walls) | Wall area | Walls, 2 coats | With ceiling |
|---|---|---|---|
| 5 × 8 ft bathroom, 1 door | 188 sq ft | 1.1 gal | 1.3 gal |
| 10 × 10 ft, 1 door, 1 window | 285 sq ft | 1.6 gal | 2.2 gal |
| 12 × 12 ft, 1 door, 2 windows | 334 sq ft | 1.9 gal | 2.7 gal |
| 12 × 14 ft, 1 door, 2 windows | 366 sq ft | 2.1 gal | 3.1 gal |
| 15 × 20 ft, 2 doors, 3 windows | 475 sq ft | 2.7 gal | 4.4 gal |
At 350 square feet per gallon. Round up to whole gallons when you buy, and keep the leftover for touch-ups.
The math
Add up the walls (2 × length + 2 × width, times the height), subtract about 20 square feet per door and 15 per window, multiply by the number of coats and divide by the coverage on the can.
When you’ll need more
- Fresh drywall, bare wood and rough texture soak up paint. Prime first, or expect less coverage than the can says.
- Big color changes, especially light over dark, often need a third coat or a tinted primer.
- Trim and doors usually take a separate quart or two of semi-gloss.
Buy it all at once
Tinted paint can vary slightly from batch to batch. Buying everything together, or mixing the cans in a bucket before you start, keeps the color even across walls.
Common questions
How much paint for a 12x12 room?
Just under 2 gallons for two coats on the walls, or about 2.7 gallons with the ceiling.
How many square feet does a gallon of paint cover?
Most interior paints list 350 to 400 square feet per coat on smooth, primed walls.
Do I need two coats of paint?
Usually, yes. Two coats give even color and better durability, especially over a different color.
Updated October 29, 2026. Figures are estimates for planning. Check product labels and local codes before you buy or build.