Paint coverage explained
Last reviewed: November 2, 2026
Coverage tells you how much area a set amount of paint should cover in one coat. Use the figure for your exact product, and multiply your area by the number of coats, since one coat's coverage doesn't include the second.
What real labels say
Coverage varies a lot between products, which is why this site doesn’t assume a number. These are the published figures we checked on the date above:
| Product | Published coverage | In m²/L |
|---|---|---|
| Sherwin-Williams SuperPaint Interior Flat | 350–400 sq ft per US gallon | 8.6–9.8 |
| Benjamin Moore Regal Select Flat | 400–450 sq ft per US gallon | 9.8–11.0 |
This isn’t a comparison of quality. The products and conditions differ, and manufacturers can change their figures. Check the label or data sheet for what you’re buying.
Why the range matters
A published figure isn’t a promise for your wall, and the choice within a range can change what you buy. Here’s what the figure does to a job of 379 sq ft with two coats:
| Coverage used | Paint needed |
|---|---|
| 450 sq ft/US gal | 1.68 US gal |
| 400 sq ft/US gal | 1.90 US gal |
| 350 sq ft/US gal | 2.17 US gal |
If your surface is rough, porous, or being painted for the first time, it’s sensible to plan with a lower figure than the headline number. How much lower depends on your surface and product, so we can’t give you a single correction.
Where coverage comes from
Coverage is really about how thick the wet paint goes on. Sherwin-Williams states its figure at a wet film of 4 mils, where a mil is a thousandth of an inch. The arithmetic shows why that matters:
- A US gallon is 231 cubic inches.
- Spread 0.004 inches thick, it covers 231 ÷ 0.004 = 57,750 square inches.
- That is about 401 sq ft, right at the top of the published 350–400 range.
In metric, 1 liter spread 0.1 mm thick covers exactly 10 m².
So coverage isn’t a fixed property of the paint. Spread it thinner and it covers more area, but the coat may not hide the surface below. That’s why a label’s figure comes with application conditions.
How many coats
Manufacturers don’t all say the same thing:
- Sherwin-Williams’ data sheet specifies two coats of SuperPaint on the surfaces it lists, with a primer on some of them.
- Benjamin Moore lists 1 or 2 coats for Regal Select Flat.
If in doubt, plan for two and read your product’s instructions.
Allowing for primer
Primer is a separate product with its own coverage. Sherwin-Williams lists its Premium Wall & Wood primer at 400 sq ft per gallon at 4 mils wet. To estimate primer with the calculator, run it separately with 1 coat and the primer’s coverage figure. The calculator won’t tell you whether you need primer, so check your paint’s instructions.
What the calculator doesn’t adjust for
The calculator uses the coverage you enter. It doesn’t correct for texture, absorption, color change, or how you apply the paint.