How Much Paint for a 15x20 Room?
2.91 gallons
Painting the walls of a 15 × 20 ft room with 8 ft ceilings, one door and two windows takes about 2.91 gallons for two coats (509 sq ft of wall at 350 sq ft per gallon). Buy 3 gallons. Add the ceiling in the calculator below if you are painting it too.
Paint for a 15 × 20 ft room by wall height (2 coats, 1 door, 2 windows)
| Wall height | Wall area | Paint needed | What to buy |
|---|---|---|---|
| 8 ft | 509 sq ft | 2.91 gallons | 3 gallons |
| 9 ft | 579 sq ft | 3.31 gallons | 4 gallons |
| 10 ft | 649 sq ft | 3.71 gallons | 4 gallons |
Adjust the numbers
The calculator below is pre-filled with the numbers above. Change any value to match your project.
Paint needed2.91 gallons
- What to buy
- 3 gallons
- Paintable area
- 509 sq ft
- Total coverage (all coats)
- 1,018 sq ft
How it is calculated
The wall area of a room is its perimeter, 2 × (length + width), multiplied by the wall height. A standard door (about 21 sq ft) and window (about 15 sq ft) are subtracted for each one you enter.
If you include the ceiling, its area (length × width) is added.
Open the full paint calculator for other shapes, a worked example and FAQs.