How much paint do I need for a 12×15 room?
Quick Answer
A 12×15 foot room with 8-foot ceilings needs approximately 2 gallons of paint for two coats on all four walls. The gross wall area is (12+15+12+15) × 8 = 432 sq ft. After subtracting one door and two windows (about 51 sq ft), you have 381 sq ft net — requiring 2.2 gallons for two coats.
Quick Reference Table
| Coats / area | Paint for 12×15 room |
|---|---|
| Walls only (1 coat) | 1 gallon |
| Walls only (2 coats) | 2 gallons |
| Walls + ceiling (2 coats) | 3 gallons |
| With primer coat | +1 gallon primer |
| Trim and doors | +1 quart |
How to Calculate It Yourself
- 1
Perimeter: (12+15+12+15) = 54 ft. × 8 ft ceiling = 432 sq ft gross.
- 2
Subtract 1 door (21 sq ft) + 2 windows (30 sq ft) = 51 sq ft. Net: 381 sq ft.
- 3
Per coat: 381 ÷ 375 = 1.02 gallons. Two coats = 2.04 gallons.
- 4
Ceiling: 12 × 15 = 180 sq ft ÷ 375 = 0.48 gallons per coat. Two coats ceiling = ~1 gallon.
Pro Tip
For a 12×15 room, buy 2 gallons of wall color. If painting the ceiling a different color, buy 1 additional gallon of ceiling white. That's your complete kit for the room.
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