Calculate how much paint you need for your room. Free online paint calculator with area, coats, and gallon estimation.
The paint calculator estimates how much paint you need for your room. Enter room dimensions and the number of coats to get wall area, ceiling area, and the number of gallons required. Standard paint coverage is approximately 350 square feet per gallon.
Wall Area = 2 × (Length + Width) × Height | Gallons = (Area × Coats) / 350Wall area is the perimeter × height. A standard gallon of interior paint covers approximately 350 sq ft per coat. Multiple coats multiply the coverage needed. Always round up and buy a little extra for touch-ups.
| Input | Output |
|---|---|
| 12×10×8 ft room, 2 coats | Walls: 352 sq ft, Ceiling: 120 sq ft, Paint: 2 gal (walls) or 3 gal (all) |
| 20×15×9 ft room, 2 coats | Walls: 630 sq ft, Ceiling: 300 sq ft, Paint: 4 gal (walls) or 6 gal (all) |
| 8×8×8 ft room, 3 coats | Walls: 256 sq ft, Ceiling: 64 sq ft, Paint: 3 gal (walls) or 3 gal (all) |