How Much Paint for a 20x20 Room?
3.37 gallons
Painting the walls of a 20 × 20 ft room with 8 ft ceilings, one door and two windows takes about 3.37 gallons for two coats (589 sq ft of wall at 350 sq ft per gallon). Buy 4 gallons. Add the ceiling in the calculator below if you are painting it too.
Paint for a 20 × 20 ft room by wall height (2 coats, 1 door, 2 windows)
| Wall height | Wall area | Paint needed | What to buy |
|---|---|---|---|
| 8 ft | 589 sq ft | 3.37 gallons | 4 gallons |
| 9 ft | 669 sq ft | 3.82 gallons | 4 gallons |
| 10 ft | 749 sq ft | 4.28 gallons | 5 gallons |
Adjust the numbers
The calculator below is pre-filled with the numbers above. Change any value to match your project.
Paint needed3.37 gallons
- What to buy
- 4 gallons
- Paintable area
- 589 sq ft
- Total coverage (all coats)
- 1,178 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.