How much paint for a 20x20 room?
3 gallons + 2 quarts of wall paint covers a 20x20 room with 8 ft ceilings in two coats. That's 590 sq ft of paintable wall (after one door and two windows), needing 3.37 gallons exactly, rounded up to cans you can buy.
| Ceiling height | Wall area | One coat | Two coats |
|---|---|---|---|
| 8 ft | 590 sq ft | 2 gal | 3 gal + 2 qt |
| 9 ft | 670 sq ft | 2 gal | 4 gal |
| 10 ft | 750 sq ft | 2 gal + 1 qt | 4 gal + 2 qt |
Wall area assumes one door (20 sq ft off) and two windows (15 sq ft each off) at 350 sq ft per gallon. More openings, less paint: every extra door is 20 sq ft you don't roll. Adding the ceiling? That's 400 sq ft overhead, 2 gal + 2 qt of flat white for two coats.
Rooms this big are living-room and great-room territory, and they usually carry taller ceilings than the 8 ft headline number. Check the 9 and 10 ft rows in the table before buying, and consider the 3/8-inch nap upgrade to a 1/2-inch: big smooth walls roll faster with a fuller cover.
Questions people ask
Does that include the ceiling?
No, the headline is walls only. The ceiling of a 20x20 room is 400 sq ft and takes 2 gal + 2 qt of flat ceiling paint for two coats. It goes in the cart as its own can.
What if my walls are textured?
Figure 300 sq ft per gallon instead of 350. For this room that means 3.93 gallons for two coats, so buy 4 gal. Orange peel and knockdown drink noticeably more than smooth drywall.
What does the paint cost?
The 3 gallons + 2 quarts runs about $176 in a $45 mid-grade line. The cost calculator prices budget and premium lines and the supplies kit.
Nearby sizes
Or start from the full room calculator with ceiling, trim, and primer options.