How much paint for a 12x12 room?
Two coats on the walls of a 12x12 room with an 8-foot ceiling takes about 2 1/4 gallons. The arithmetic, and quantities for every room size.
About 2.2 gallons for two coats — buy 2 gallons and 1 quart.
344 ft² of wall after taking out a door and a window, times two coats, at 350 ft² per gallon.
How that is worked out
- Perimeter × height gives the gross wall area: 48' × 8' = 384 ft².
- Take off the openings — about 40 ft² for one door and one window — leaving 344 ft² to paint.
- Two coats is 688 ft² of coverage. At 350 ft² per gallon and a roller's share of waste, that is 2.2 gallons.
Walls only, 8' ceiling, one door and one window taken out
| Room | Wall area | One coat | Two coats | Buy for two coats |
|---|---|---|---|---|
| 8' × 8' | 216 ft² | 0.7 gal | 1.4 gal | 1 gal + 2 qt |
| 10' × 10' | 280 ft² | 0.9 gal | 1.8 gal | 2 gal |
| 12' × 12' | 344 ft² | 1.1 gal | 2.2 gal | 2 gal + 1 qt |
| 14' × 14' | 408 ft² | 1.3 gal | 2.6 gal | 2 gal + 3 qt |
| 16' × 16' | 472 ft² | 1.5 gal | 3.0 gal | 3 gal |
| 20' × 20' | 600 ft² | 1.9 gal | 3.8 gal | 4 gal |
Worth knowing
- This is walls only. A ceiling adds its own area — 144 ft² on a 12x12 room, which is another gallon for two coats.
- 350 ft² per gallon is a middling figure and every can states its own. Coverage drops a long way on bare drywall, on a rough or textured surface, and on anything porous — prime first and the topcoat goes further.
- A big colour change costs an extra coat, and going light over dark can cost two. Tinted primer is cheaper than a third coat of finish paint.
- Spraying uses noticeably more paint than rolling for the same area — there is overspray and there is what stays in the gun and the hose. Brushing uses the least and takes the longest.
Work out your own numbers
- Paint and finish coverage
Gallons from an area and a coat count, with the cans to buy for brush, roller or spray.
- Wainscoting layout
Even picture-frame boxes across a wall, drawn as an elevation with the cut lengths underneath.
Related questions
- How much paint do I need for a 12x12 room?
- About 2 1/4 gallons for two coats on the walls of a room with an 8-foot ceiling, once a door and a window are taken out — which is two gallons and a quart, or just buy three. Add roughly another gallon if you are painting the ceiling too. The leftover is your touch-up paint, and it is the same batch as the walls.
- How many square feet does a gallon of paint cover?
- Around 350 to 400 ft² on a smooth, primed, previously painted wall. Bare drywall drinks it and a textured surface has more area than its dimensions suggest, so both come in well under. The number on the can is measured under good conditions — treat it as the best case.
- Do I need one coat or two?
- Two, nearly always. One coat over a similar colour on a sound surface can look fine when wet and patchy when dry, especially in raking light. The exception is a genuine touch-up with the same paint from the same can. Over a colour change, budget for two and be ready for three.