Typical coverage
| Product | Coverage per gallon |
|---|---|
| Wall paint (Sherwin-Williams’ general figure) | 350 to 400 sq ft |
| Primer (Sherwin-Williams’ general figure) | 200 to 300 sq ft |
| Benjamin Moore Fresh Start 046 primer | 400 to 450 sq ft |
A quart is a quarter of a gallon, so it covers about 85 to 100 sq ft of wall paint. The figure on your can, or the product’s technical data sheet, is the one to use. Sherwin-Williams notes that the surface and how you apply the paint change the result, and textured walls take more.
Working out how many gallons
- Add up the length of every wall to get the perimeter.
- Multiply by the wall height to get the square footage.
- Measure each door and window (width × height) and take them off.
- Multiply by the number of coats you plan.
- Divide by the coverage on the can and round up.
Example. A 12 × 14 foot room with 8 foot walls has a perimeter of 2 × (12 + 14) = 52 ft, so 52 × 8 = 416 sq ft. Take off one 3 × 7 ft door (21 sq ft) and two 3 × 4 ft windows (12 sq ft each): 416 − 45 = 371 sq ft. Two coats is 742 sq ft.
- At 400 sq ft per gallon: 742 ÷ 400 = 1.86, so 2 gallons.
- At 350 sq ft per gallon: 742 ÷ 350 = 2.12, so 2 gallons is not quite enough. Buy 2 gallons and a quart.
The coverage figure you use can change what you buy, so use the one for your paint.