Paint Calculator
Find how many gallons of paint a room's walls and ceiling need, less doors and windows, for the coats you choose.
Change the values and press Calculate to work out your own figures.
Paint for a room
Enter the room's size and count the doors and windows.
Show the working
- area = walls (+ ceiling) − 20 sq ft a door − 12 sq ft a window
- gallons = area × 2 coats ÷ 350 sq ft a gallon
From the area
Enter the area to paint.
Show the working
- area as entered
- gallons = area × 2 coats ÷ 350 sq ft a gallon
How to use it
Enter the room's size and count the doors and windows. Enter the area to paint.
Lengths can be decimals, fractions or tape entries such as 12' 6 1/2" (in feet or inches). Prices are optional.
Key facts
gallons = (walls (+ ceiling) − 20 sq ft a door − 12 a window) × coats ÷ coverage
Coverage
Smooth, primed walls reach the label's coverage; rough or porous surfaces and big color changes take more.
Questions
How much paint for a 12 × 10 ft room?
1.76 gallons for two coats on the walls, with one door and two windows.
Formulas
gallons = (walls (+ ceiling) − 20 sq ft a door − 12 a window) × coats ÷ coverage
Sources
Limitations
- Material densities are typical values (the midpoint of the commonly published range); real loads vary with moisture, grading and compaction, so check with your supplier or type in their density.
- Tank results are the geometric volume; real tanks have wall thickness and fittings.