Paint for a 20 × 20 room
Short answer
A 20 × 20 ft room with an 8-ft ceiling needs about 4 gallons of paint for two coats — that's roughly 589 sq ft of wall after doors and windows.
Paint needed
4 gal
Paint cost
$120–$180
Wall area
640 sq ft
Paintable
589 sq ft
Painting a 20 × 20 room
A 20 × 20-foot room with an 8-ft ceiling has about 640 sq ft of wall — that's the perimeter, 2 × (length + width), times the ceiling height. Subtract a door (~21 sq ft) and two windows (~15 sq ft each) and you're actually painting roughly 589 sq ft.
At 2 coats with standard paint (~375 sq ft per gallon), that works out to about 4 gallons, or $120–$180 in paint. A taller ceiling, an extra coat, a primer coat on bare drywall, or a bold color change all push that up — so round up rather than down.
What changes how much you need
| Factor | Effect on paint needed |
|---|---|
| Number of coats | Two coats is standard — it doubles the coverage area vs a single coat |
| Paintable area | ~589 sq ft here after subtracting doors and windows |
| Paint grade | Economy covers ~350 sq ft/gal, premium ~400 — better paint also hides in fewer coats |
| Surface & color | Bare drywall or a big color change needs primer or an extra coat |
| Openings | Each door (~21 sq ft) and window (~15 sq ft) is area you don't paint |
| Wall texture | Textured, rough, or porous walls drink noticeably more paint than smooth ones |
Cost by paint grade
Gallons and paint cost for this 20 × 20 room at two coats, by paint quality.
| Grade | Coverage | Gallons | Paint cost |
|---|---|---|---|
| Economy | 350 sq ft/gal | 4 | $80–$120 |
| Standard | 375 sq ft/gal | 4 | $120–$180 |
| Premium | 400 sq ft/gal | 3 | $135–$210 |
Painting tips
- Buy about 10% more than the estimate — you'll want it for a second coat on tricky spots and future touch-ups.
- Prime bare drywall, patches, and any drastic color change first; primer stops the topcoat from soaking in unevenly.
- Box your gallons — mix them together in one bucket — so the color stays consistent from the first wall to the last.
- A pricier paint that covers in one or two coats can beat a cheap one that needs three — compare cost per finished wall, not per gallon.
Your exact room
Open the paint calculatorOther room sizes
Frequently asked questions
How much paint for a 20 × 20 room?
About 4 gallons for two coats on the walls of a 20 × 20 ft room with an 8-ft ceiling (roughly 589 sq ft after one door and two windows).
How much does it cost to paint a 20 × 20 room?
Paint alone runs about $120–$180 for a 20 × 20 room at two coats. Add primer, supplies, or labor on top.
Do I need one or two coats?
Two coats is standard for even color and coverage, especially over a different color. One coat can work when repainting the same color with premium paint. The calculator lets you switch coats.