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.
Assumptions to Check
Before ordering materials, confirm the dimensions, product coverage, waste factor, and local installation requirements for your project. Manufacturer coverage tables and local code rules can change the final quantity, especially for structural work, exterior projects, and irregular layouts.
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