18×18 room: paint by wall height
| Wall height | Paintable sq ft | Gallons (2 coats) | Buy |
|---|---|---|---|
| 8 ft | 526 | 3.01 | 4 |
| 9 ft | 598 | 3.42 | 4 |
| 10 ft | 670 | 3.83 | 4 |
1 door and 2 windows deducted; 350 sq ft per gallon.
Worked example
Perimeter: 2 × (18 + 18) = 72 ft. With 8 ft walls: 576 sq ft, minus 20 (door) and 30 (two windows) = 526 sq ft. Two coats: 1052 ÷ 350 = 3.01 gallons. The ceiling adds 324 sq ft per coat (about 1.85 gallons for two coats).
Frequently asked questions
How many gallons to paint a 18×18 room?
About 3.01 gallons for two coats on 8 ft walls (buy 4).