Paint Coverage: How Many Sq Ft per Gallon?
Quick answer: a gallon of paint covers about 350 sq ft with one coat on smooth, sealed walls. A 12×12 room needs ~1 gallon per coat. Here's how to count coats, ceilings, and waste.
- Coverage per gallon
- Finish & surface factors
- Room-by-room chart
- Worked example
- Coats & ceilings
- Common mistakes
Coverage per gallon
Most paints state 350 sq ft per gallon on the label. That assumes smooth, sealed walls and one coat. On rough texture, unpainted drywall, or wood, coverage drops to 200–300 sq ft because the paint soaks in. Always read the label on the can you buy — brands differ.
Finish & surface factors
Flat and matte finishes cover slightly more than satin or semi-gloss, which are thinner and can need an extra coat for even coverage. Dark, heavy pigments cover less than light ones. And a fresh primer coat always improves how far your finish paint goes — primed walls are a known, sealed base.
Room-by-room chart
| Room | Wall sq ft (approx) | 1 coat (gal) | 2 coats (gal) |
|---|---|---|---|
| 10×10 bedroom | ~320 | 1 | 2 |
| 12×12 bedroom | ~380 | 1.1 | 2.2 |
| 12×15 living room | ~430 | 1.2 | 2.5 |
| 12×12 kitchen | ~380 | 1.1 | 2.2 |
These assume 8-ft ceilings and subtract standard windows and doors. Add the ceiling area if you're painting it too.
Worked example
A 12×12 room with 8-ft ceilings, two coats:
- Walls = perimeter × height = (12×4) × 8 = 384 sq ft, minus door/window ≈ 348 sq ft
- One coat = 348 ÷ 350 ≈ 1 gallon
- Two coats ≈ 2 gallons → round to 2–2.5
Buying a full extra gallon for touch-ups later is common — paint stores mix from the same batch, and matching a second purchase is never exact.
Coats & ceilings
Two coats are standard for walls. For the ceiling, add length × width to your total (a 12×12 ceiling is 144 sq ft ≈ 0.4 gallon per coat) and prime first if it's new drywall. Count each coat as its own pass through the coverage math — a "two-coat job" doubles the gallons, not the area.
Common mistakes
- Using label coverage for one coat only. Two coats = double the paint.
- Ignoring rough surfaces. Textured walls eat 20–30% more paint.
- Forgetting the ceiling. It's real area that must be in the count.
- Not buying enough for touch-ups. Same-batch paint saves matching headaches.
FAQ
A gallon of paint covers about 350 square feet with one coat on smooth, sealed walls. Rough or porous surfaces drop that to 200–300 square feet.
A 12×12 room with 8-ft ceilings has about 380 sq ft of wall. One coat needs ~1.1 gallons; two coats need ~2.2 gallons — so about 1 gallon per coat, or 2 gallons for two coats.
Yes — flat and matte finishes cover slightly more than glossy ones, which are thinner and may need an extra coat. Heavier pigments also reduce coverage per gallon.
Measure perimeter × height for walls, add the ceiling area (length × width), subtract windows and doors, then divide by 350 sq ft per gallon and multiply by the number of coats.