Formula and input notes
Gallons = [(wall run × height − openings) × coats ÷ coverage per gallon] × (1 + waste ÷ 100)
| Input | Practical note |
|---|---|
| Coats | Enter the number of full coats receiving coverage; primer or products with different spread rates should be calculated separately. |
Worked paint example
Paint Calculator example: (34.6 ft × 7.84 ft − 60 ft²) × 2 coats ÷ 350 ft²/gal × 1.1 = 1.33 gal, which the tool rounds to 2 whole gallons to buy.
Package rounding and usable yield
Round finish paint to purchasable container sizes while keeping primer, ceiling paint, trim enamel, and different colors separate.
Why the label value may not match the floor or wall
Porous repairs, texture, color change, application method, primer, overspray, and product-specific spread rate affect gallons.
Questions specific to this calculation
Should openings and multiple coats be entered separately?
Enter total wall run, wall height, openings, coat count, and the coverage stated for the selected coating and surface condition.