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Paint Calculator
Estimate the gallons of paint for a room from its size, wall height, doors, windows and number of coats - walls and ceiling.
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How to use it
- Enter the room length, width and wall height.
- Count doors and windows (about 20 ft² and 15 ft² are subtracted each).
- Most jobs need 2 coats; add a primer coat for big color changes or bare drywall.
- Coverage is printed on the can - 350-400 ft² per gallon is typical.
How it works
Wall area = 2 × (length + width) × height, minus 20 ft² per door and 15 ft² per window. Paint = area × coats ÷ coverage. Buy whole gallons; a quart is a quarter gallon, handy for touch-ups.
FAQ
How much paint do I need for a 12 × 12 room?
With 8 ft walls, one door and two windows: about 334 ft² of wall, so roughly 2 gallons for two coats.
How many square feet does a gallon of paint cover?
Usually 350-400 ft² per coat on smooth, primed walls; less on textured or porous surfaces.
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