Paint Coverage Calculator
Find out how many gallons of paint you need for any room.
3
Gallons Needed
543
Net Wall Area (sq ft)
1086
Total Coverage (sq ft)
How the Paint Coverage Calculator Works
This calculator estimates how many gallons of paint you'll need to cover the walls of a room, so you can buy the right amount before starting a project.
It calculates total wall area from your room's perimeter and ceiling height, subtracts space taken up by doors and windows, multiplies by the number of coats you plan to apply, and divides by a standard coverage rate of 400 square feet per gallon.
Example: a 20×15 ft room with 9 ft ceilings has a wall area of 2×(20+15)×9 = 630 sq ft. Subtracting 2 doors (42 sq ft) and 3 windows (45 sq ft) leaves 543 sq ft. With 2 coats, that's 1,086 sq ft of painted surface, or about 3 gallons of paint.