Coverage guide
How Many Gallons of Paint Do I Need?
A good rule of thumb: one gallon covers about 350 to 400 square feet of wall with one coat. For two coats on a typical room, plan on roughly 1 gallon per 200 sq ft of wall. The table and calculator below make it exact.
Gallons by room size (two coats, 8 ft walls)
| Room | Wall area | Gallons (2 coats) |
|---|---|---|
| 10 x 10 bedroom | ~300 sq ft | ~1.5 gal |
| 12 x 12 bedroom | ~384 sq ft | ~2.5 gal |
| 10 x 12 room | ~352 sq ft | ~2 gal |
| 14 x 16 room | ~560 sq ft | ~3.5 gal |
| 16 x 20 living room | ~800 sq ft | ~5 gal |
These assume one door and two windows subtracted, two coats, and standard 350 sq ft/gallon coverage. Add a third coat or a ceiling and buy more.
The formula
Gallons = (wall area x coats x waste) / coverage per gallon. Wall area is perimeter x height minus doors and windows. A 10% waste factor covers cuts, touch-ups, and the paint left in the tray.
Tips to avoid running short
- Round up to the next whole or half gallon; a half-gallon left over is cheaper than a second trip.
- Buy all cans from the same batch number so color stays consistent across the room.
- For open-plan spaces, calculate the whole perimeter together rather than room by room.
FAQ
How many gallons for a 10x10 room?
About 1.5 gallons for two coats on 8 ft walls, assuming one door and two windows. Buy 2 gallons to be safe.
Do I need primer too?
On bare drywall or a big color change, yes. Primer is a separate gallon counted at the same wall area, usually one coat.
Why does coverage vary so much?
Surface texture, color change, and paint quality all matter. Rough or unprimed walls soak up more; deep colors need more coats.
Independent guide. Use the Paint Coverage Calculator for precise gallons, or the Paint Calculator to add cost and supplies.