How much does a gallon of paint cover?
350 to 400 square feet per coat, with a lot of caveats.
A gallon of interior emulsion covers 350 to 400 square feet in one coat on a prepared surface. For two coats, that is 175 to 200 sq ft per gallon.
Realistic coverage by surface
The coverage on the tin is measured in ideal conditions: a smooth, sealed wall with the right roller. Real jobs rarely match it.
Swipe to see the whole table
| Surface | sq ft per gallon per coat | Why |
|---|---|---|
| Smooth, previously painted wall | 350-400 | Nothing soaks in: nominal coverage |
| New unprimed drywall | 200-280 | Very absorbent, the first coat sinks in |
| Primed drywall | 300-350 | Sealed, but still thirstier than old paint |
| Textured or knockdown finish | 200-280 | Far more real surface than it looks |
| Ceilings | 280-350 | Harder to roll evenly, more paint unloaded |
Using it to work out a room
Once you know the coverage, the sum is direct:
For 384 sq ft of wall, two coats at 350 sq ft/gal: 384 x 2 / 350 = 2.2 gallons, plus waste. If that wall were unprimed drywall at 250 sq ft/gal, you would need 3.1 gallons: 40 % more for the same job.
The first coat and the rest do not cover the same
The first coat on an absorbent surface disappears much faster than the second, because part of the paint soaks in rather than staying on top. That is what primer is for: it seals the surface so the finish coats cover what the tin promises. On new drywall, priming is cheaper than burning finish paint as a sealer.
What the figure on the tin actually means
Manufacturers state coverage in square feet per gallon per coat. A tin claiming "up to 400 sq ft" covers 400 square feet once. With two coats that gallon reaches 200 sq ft. The "up to" matters too: it is a maximum under optimal conditions.
Sources and methodology
The ranges in the table are common figures for interior emulsion. There is no universal value because it depends on the product, the surface and the tool, which is why the calculator lets you enter the real coverage of the tin you are buying.
Frequently asked questions
How many square feet does a gallon of paint cover?
350 to 400 square feet in one coat on a smooth prepared wall. On new drywall or textured surfaces it falls to 200-280 sq ft.
How much paint do I need per square foot?
About 0.0029 gallons per square foot per coat at 350 sq ft/gal, or roughly a gallon for every 175 sq ft painted twice.
Is coverage per coat or total?
Per coat. A stated 400 sq ft per gallon means 400 square feet painted once. Two coats halve it to 200.
Why does my tin cover less than it claims?
Almost always the surface. An absorbent, textured or unprimed wall has more real surface area and drinks more paint than the smooth panel in the manufacturer's test.