Paint calculator
Work out how much paint you need for a room, allowing for doors, windows and the number of coats.
Buy
- Wall area to paint
- Ceiling
- Paint needed
Estimates only.
How this calculator works
Enter the room's length, width and wall height. The calculator works out the wall area, takes off about 21 square feet for each door and 15 square feet for each window, then multiplies by the number of coats.
It divides that by your paint's coverage per gallon and tells you what to buy, rounding up to whole gallons, or gallons plus a quart when you only need a little extra.
Tips
- Check the can for its coverage figure and enter it if it's different.
- Buy a little extra for touch-ups later, and keep it labeled with the room.
- Paint ceilings separately, usually in flat ceiling white. Turn on the ceiling option to include it.
- Mix cans together in a larger bucket if you buy more than one, so the color is even.
Common questions
Most interior paint covers about 350 to 400 square feet per gallon for one coat on smooth walls. Rough or textured walls, bare drywall and dark colors can need more.
Usually, yes. Two coats give even color and better durability, especially when changing colors. One coat can be enough when repainting the same color in good condition.
Use primer on bare drywall, patched areas, stains, glossy surfaces, or when going from a dark color to a light one. Paint-and-primer products can work on walls already in good shape.