Paint Coverage Calculator
Paint coverage = gallons × spread rate ÷ coats. At 350 ft² per gallon — typical for smooth, primed walls — 2 gallons cover 700 ft² in one coat, or 350 ft² with two. Use it to check whether the paint you have is enough; to estimate a new job from wall sizes, use the Paint Calculator.
How it's calculated: Area covered = (gallons × spread rate) ÷ coats.
Result appears here
Fill in the fields and press Calculate.
Formula, calculation, assumptions and sources
Area covered = (gallons × spread rate) ÷ coats
Run the calculation to see each step with your own numbers.
2 gallons in hand, 350 ft²/gal, planning 2 coats.
One coat covers 2 × 350 = 700 ft²
Two coats: 700 ÷ 2 = 350 ft²
- Spread rate is the effective figure for your paint and surface — a real second coat covers a bit more than the first, so this is slightly conservative for multi-coat work.
- Coverage is uniform across the whole area, with no allowance for edges, trim cut-in or spray overspray. Brush-and-roll work is close to the rate; spraying loses 20–40% to overspray.
- The paint is stirred, at working consistency and not over-thinned — thinning past the manufacturer's limit stretches the coverage but weakens the film.
- How far does one gallon of paint go?
- About 350–400 ft² on smooth, primed drywall for one coat; 250–300 on textured, porous or bare surfaces. The calculator uses whatever rate you give it.
- Does a second coat cover as much as the first?
- Slightly more, because the surface is already sealed, so this calculator is a little conservative for multi-coat work. The difference is small enough to ignore for ordering.
- How many square feet does 2 gallons of paint cover?
- About 700 ft² for one coat at 350 ft² per gallon, or 350 ft² if you apply two coats. On textured or bare surfaces, where the spread rate is closer to 250–300 ft², expect less.
Spread rate
≈ 350 ft² per US gallon per coat for interior latex on a primed, smooth surface. Paint-manufacturer data sheets (Sherwin-Williams, Benjamin Moore) quote 350–400. Rougher/porous surfaces are lower. Editable.
About the Paint Coverage Calculator
The Paint Coverage Calculator converts between paint quantity, area and coats at a spread rate you choose — how far a given number of gallons will go, or how much paint an area needs. Use it to check whether the paint you already have is enough, or to work backwards from a leftover can. The Paint Calculator is the better starting point when you're estimating a fresh project from wall dimensions.
What you enter
- Paint on hand (gallons)
- Coverage (ft²/gal/coat)
- Coats
What you get back
- Area this covers — At the number of coats you entered.
- Area at one coat — the exact result of the calculation.
The formula, a worked example, the assumptions behind it and the sources are shown in full below the calculator.
Related calculators
- Paint Calculator — Paint in gallons or litres for a project from surface area and coats.
- Wall Paint Calculator — Paint for walls only, with doors and windows deducted.
- Ceiling Paint Calculator — Paint for a ceiling of a given area and number of coats.
Related articles
- How Much Paint Coverage Should You Expect? — Paint coverage is usually stated per gallon on the can, but surface texture, porosity and application method can all shift real-world coverage.
Part of the Painting calculators.