How Much Paint for a Room? Gallons for Every Common Room Size

By Save On Home Decor · Updated Nov 1, 2026 · How we calculate

Find your room size and ceiling height. Each line assumes one door, two windows and two coats.

Room	Ceiling	Wall area	Walls, 2 coats	Ceiling, 2 coats
10 x 10 ft	8 ft	269 sq ft	2 gal	1 gal
10 x 10 ft	9 ft	309 sq ft	2 gal	1 gal
10 x 10 ft	10 ft	349 sq ft	2 gal	1 gal
10 x 12 ft	8 ft	301 sq ft	2 gal	1 gal
10 x 12 ft	9 ft	345 sq ft	2 gal	1 gal
10 x 12 ft	10 ft	389 sq ft	2 gal + 1 qt	1 gal
12 x 12 ft	8 ft	333 sq ft	2 gal	1 gal
12 x 12 ft	9 ft	381 sq ft	2 gal + 1 qt	1 gal
12 x 12 ft	10 ft	429 sq ft	2 gal + 2 qt	1 gal
12 x 14 ft	8 ft	365 sq ft	2 gal + 1 qt	1 gal
12 x 14 ft	9 ft	417 sq ft	2 gal + 2 qt	1 gal
12 x 14 ft	10 ft	469 sq ft	3 gal	1 gal
14 x 16 ft	8 ft	429 sq ft	2 gal + 2 qt	1 gal + 2 qt
14 x 16 ft	9 ft	489 sq ft	3 gal	1 gal + 2 qt
14 x 16 ft	10 ft	549 sq ft	3 gal + 1 qt	1 gal + 2 qt
15 x 20 ft	8 ft	509 sq ft	3 gal	2 gal
15 x 20 ft	9 ft	579 sq ft	3 gal + 2 qt	2 gal
15 x 20 ft	10 ft	649 sq ft	4 gal	2 gal
16 x 20 ft	8 ft	525 sq ft	3 gal	2 gal
16 x 20 ft	9 ft	597 sq ft	3 gal + 2 qt	2 gal
16 x 20 ft	10 ft	669 sq ft	4 gal	2 gal
20 x 20 ft	8 ft	589 sq ft	3 gal + 2 qt	2 gal + 2 qt
20 x 20 ft	9 ft	669 sq ft	4 gal	2 gal + 2 qt
20 x 20 ft	10 ft	749 sq ft	4 gal + 2 qt	2 gal + 2 qt

Figures use 350 sq ft per gallon per coat, the low end of what paint makers publish, rounded up to the quart, after subtracting 21 sq ft for one door and 15 sq ft for each of two windows. Your own room in seconds: the paint calculator.

When to buy more

Big color changes (dark to light or a deep red or navy) often need a third coat or a tinted primer.
Textured walls, new drywall and bare plaster soak up more paint.
Keep a quart for touch-ups, labeled with the room and the color formula.