How Much Paint for a 20x20 Room?
A 20x20 ft room (400 sq ft) with 8 ft ceilings needs about 4 gallons of paint for two coats on the walls, or 6 gallons if you also paint the ceiling. That assumes 1 door and 2 windows and 350 sq ft of coverage per gallon.
Paint for a 20x20 room
| What you paint | Area | Exact gallons | Buy |
|---|---|---|---|
| Walls, 2 coats | 590 sq ft | 3.4 | 4 |
| Walls, 1 coat (touch-up or same color) | 590 sq ft | 1.7 | 2 |
| Walls, 3 coats (dark to light color change) | 590 sq ft | 5.1 | 6 |
| Walls and ceiling, 2 coats | 990 sq ft | 5.7 | 6 |
| Primer for the walls, 1 coat | 590 sq ft | 2.4 | 3 |
Walls = 2 × (20 + 20) × 8 = 640 sq ft, minus 50 sq ft for 1 door (20 sq ft) and 2 windows (15 sq ft each). The ceiling adds 400 sq ft. Gallons to buy are rounded up to a whole gallon.
Adjust for your room
More windows, taller ceilings, textured walls or trim change the answer. Porous or textured walls soak up more paint, so figure on 250 to 300 sq ft per gallon instead of 350. Enter your own ceiling height, doors, windows, coats and price in the paint calculator. Painting a whole floor or house? Add up each room, then buy by the 5-gallon bucket if the total is over 4 gallons of one color. Baseboards, trim and closets are not counted here; for a floor, see the tile and flooring calculator.
Frequently asked questions
How much paint do I need for a 20x20 room?
For the walls of a 20x20 ft room with 8 ft ceilings, 2 coats, 1 door and 2 windows, you need about 4 gallons of paint. Painting the ceiling too brings it to 6 gallons.
How many square feet of wall is a 20x20 room?
The four walls total 640 square feet (80 ft around × 8 ft high). After subtracting 50 sq ft for the door and windows, about 590 sq ft is left to paint.
How much paint for a 20x20 room with a primer?
Primer covers about 250 sq ft a gallon, so one coat over 590 sq ft takes 3 gallons of primer in addition to the 4 gallons of paint. Skip primer on clean, previously painted walls if you stay with a similar color.
How many gallons for a 20x20 room with a different color?
Going from a dark to a light color often takes 3 coats: 6 gallons for the walls of a 20x20 room. A primer or a tinted primer can save a coat.
Other room sizes
Planning figures for interior walls. Coverage varies by paint and surface, so check the can.