How much paint for a 18x18 room?
A 18x18 ft room has about 540 sq ft of wall after subtracting one door and one window. For two coats you need roughly 3.1 gallons.
For 2 coats, walls, 8 ft ceiling
3.1 gallons (~4 cans)
About 540 sq ft of paintable wall.
Calculate your exact amount
Adjust the height, coats, doors and windows for your room:
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Paint needed for a 18x18 room (chart)
| Ceiling height | 1 coat | 2 coats | 3 coats |
|---|---|---|---|
| 8 ft | 1.5 gal | 3.1 gal | 4.6 gal |
| 9 ft | 1.7 gal | 3.5 gal | 5.2 gal |
| 10 ft | 2 gal | 3.9 gal | 5.9 gal |
Based on ~350 sq ft per gallon per coat, minus one door and one window.
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Shop interior paint →How we calculated this
- Wall area = 2 × (length + width) × height = 2 × (18 + 18) × 8 = 576 sq ft.
- Minus one door (21 sq ft) and one window (15 sq ft) = 540 sq ft.
- × 2 coats ÷ 350 sq ft per gallon = 3.1 gallons.
Frequently asked questions
- How many gallons of paint for a 18x18 room?
- About 3.1 gallons for two coats of walls with 8 ft ceilings, or 1.5 gallons for a single coat.
- How much paint do I need for a 18x18 room with high ceilings?
- Use the chart above — a 10 ft ceiling raises it to about 3.9 gallons for two coats.