How this calculator works
1. Paintable wall area
2. Paint quantity
Coverage is printed on every can, usually as a range. Use the low end for textured walls, fresh drywall or a dramatic color change, and the high end for smooth, previously painted walls in a similar color.
3. What to buy
The calculator rounds to whole gallons. If the remainder is half a gallon or less and you entered a quart price, it tops up with quarts instead, since a quart often costs a large share of a gallon. A remainder above half a gallon rounds to another full gallon.
4. Cost
Frequently asked questions
Do I really need two coats?
Usually, when changing color. One coat can be enough when repainting the same color on a sound surface with a high-hiding paint. When in doubt, plan for two. The how much paint guide covers when one coat works.
Does this include trim and doors?
No. Trim, baseboards, door faces and closet interiors are excluded. They usually take a different sheen, and often a different product, so estimate them separately.
How do I estimate a room with a vaulted ceiling?
Enter the wall height at the eaves, then work out each triangular gable section separately: ½ × base × rise. Multiply that area by your coats and divide by coverage to get the extra gallons, and add them to the result.
Planning the full budget? Our interior painting budget guide lists every cost beyond the paint itself.