Home & Cooking
Paint Calculator
Estimate how much paint you need for a room. Accounts for doors, windows, multiple coats, and coverage rate per gallon.
Room dimensions
Typical interior latex paint covers 350-400 sqft per gallon. Check the can for the actual rate.
Paint needed
3 gallons
(2.18 gal, or 8.71 quarts) for 2 coats.
Total wall area
432 sqft
After doors+windows
381 sqft
Frequently Asked Questions about the Paint Calculator
How much paint do I need for one room?
For a 12 x 15 ft room with 8 ft ceilings and no doors or windows, the calculator finds a perimeter of 54 ft, giving 432 sqft of wall area. At the default 350 sqft per gallon, one coat needs about 1.23 gallons, so buy 2. Add more coats and the estimate scales up proportionally.
How many coats of paint do I need?
Two coats is the standard for even coverage and long-term durability. One coat can work when you are repainting a very similar color over a sound existing finish. Going from a light wall to a deep or saturated color typically takes 2-3 coats to eliminate bleed-through.
What does 'coverage per gallon' mean?
It is the wall area one gallon covers in a single coat. Most interior latex paints cover 350-400 sqft per gallon on smooth, primed surfaces. Rough or textured walls absorb more paint, so use the lower end of the range and budget at least 10-15% extra for heavier textures.
Should I include doors and windows?
Subtract them. The calculator deducts 21 sqft per door (a standard 3 x 7 ft door) and 15 sqft per window (a standard 3 x 5 ft window) from the total wall area. Enter your counts and the deduction happens automatically.
How much paint for the ceiling?
Multiply room length by width to get ceiling area. A 12 x 15 ft ceiling is 180 sqft, which takes about 0.51 gallons per coat at 350 sqft per gallon. The calculator covers walls only, so calculate ceiling paint separately and add the quantities when you shop.
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