Paint Calculator
Enter the room’s length, width and ceiling height, and the number of doors and windows. The calculator subtracts about 21 sq ft per door and 15 sq ft per window, and assumes a gallon covers 350 sq ft.
Two coats are standard when changing color or painting fresh drywall (after primer). Rounding to gallons and quarts keeps leftover paint to a minimum.
How it’s calculated
- Wall area = 2 × (length + width) × height − doors − windows.
- Gallons = wall area × coats ÷ 350.
- Ceiling paint = length × width ÷ 350 per coat.
Paint for common room sizes
- 8×8
- 8×9
- 8×10
- 8×11
- 8×12
- 8×13
- 8×14
- 8×15
- 8×16
- 8×18
- 8×20
- 8×24
- 9×9
- 9×10
- 9×11
- 9×12
- 9×13
- 9×14
- 9×15
- 9×16
- 9×18
- 9×20
- 9×24
- 10×10
- 10×11
- 10×12
- 10×13
- 10×14
- 10×15
- 10×16
- 10×18
- 10×20
- 10×24
- 11×11
- 11×12
- 11×13
- 11×14
- 11×15
- 11×16
- 11×18
- 11×20
- 11×24
- 12×12
- 12×13
- 12×14
- 12×15
- 12×16
- 12×18
- 12×20
- 12×24
- 13×13
- 13×14
- 13×15
- 13×16
- 13×18
- 13×20
- 13×24
- 14×14
- 14×15
- 14×16
- 14×18
- 14×20
- 14×24
- 15×15
- 15×16
- 15×18
- 15×20
- 15×24
- 16×16
- 16×18
- 16×20
- 16×24
- 18×18
- 18×20
- 18×24
- 20×20
- 20×24
- 24×24
Questions
- How much paint do I need for a 12 × 12 room?
- With 8 ft ceilings, one door and two windows, the walls are about 333 sq ft: just under 2 gallons for two coats.
- How many square feet does a gallon of paint cover?
- About 350 to 400 sq ft per coat on smooth, primed walls. Textured or porous surfaces take more.
- Should I buy quarts or a gallon?
- If you need more than about 2½ quarts, a gallon is cheaper.