How much paint do I need for a 15×20 room?
Short answer: a 15×20 room with 8-foot ceilings needs about 2.7 gallons of paint for two coats. With a 10% safety margin, buy 3 × 1-gallon can.
A 15×20 room is usually a living room. The estimate below assumes 2 doors and 3 windows, which is typical for that size; adjust them in the calculator if yours differ.
How we got that number
- Wall area: 2 × (15 + 20) × 8 ft = 560 sq ft
- Minus 2 doors (20 sq ft each) and 3 windows (15 sq ft each) = 475 sq ft to paint
- Two coats at 350 sq ft per gallon = 2.71 gallons
- Plus a 10% safety margin for textured walls, patches, and touch-ups = 2.99 gallons
Can labels assume smooth, primed walls. Textured or rough walls use more paint, which is why we add 10%. Very rough surfaces like brick can need even more.
With taller ceilings
| Ceiling height | Wall area | Paint needed | Buy (incl. 10% margin) |
|---|---|---|---|
| 8 ft | 475 sq ft | 2.7 gal | 3 × 1-gallon can |
| 9 ft | 545 sq ft | 3.1 gal | 3 × 1-gallon can + 2 × quart |
| 10 ft | 615 sq ft | 3.5 gal | 1 × 5-gallon bucket |
Painting the ceiling too?
The 15×20 ceiling is 300 sq ft. Two coats need about 1.7 gallons of flat ceiling paint, so buy 2 × 1-gallon can (with the 10% margin).
What the wall paint will cost (8 ft ceilings)
| Paint grade | Price | Paint cost |
|---|---|---|
| Budget | $30/gal | $90 |
| Mid-range | $45/gal | $135 |
| Premium | $70/gal | $210 |
Before sales tax and supplies. Prices are typical US store prices and vary by brand and area.
Customize this room in the calculator →
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