Paint Calculator
Enter the room's length, width and wall height in feet. One gallon covers about 350 sq ft per coat on smooth, primed walls.
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sq ft
$
Each door takes off 20 sq ft and each window 15 sq ft.
Result–
Paint for common rooms (2 coats, walls only)
| Room | Wall area | Gallons |
|---|---|---|
| 10 × 10 ft, 8 ft walls | 270 sq ft | 1.5 |
| 10 × 12 ft, 8 ft walls | 302 sq ft | 1.7 |
| 12 × 12 ft, 8 ft walls | 334 sq ft | 1.9 |
| 12 × 14 ft, 8 ft walls | 366 sq ft | 2.1 |
| 14 × 16 ft, 8 ft walls | 430 sq ft | 2.5 |
| 16 × 20 ft, 8 ft walls | 526 sq ft | 3 |
Gallons = (wall area − doors − windows) × coats ÷ coverage
Rough, porous or dark-to-light color changes may need a primer coat or a third coat.
Questions
How much does a gallon of paint cover?
About 350–400 sq ft per coat on smooth, primed surfaces; less on textured or bare drywall.
Do I need two coats?
Usually. Two coats give even color and better durability, especially when changing colors.