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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, you need roughly 1.2 gallons for one coat of standard wall paint (350 sqft per gallon coverage). Round up: it's always better to have leftover than to run out mid-job.
How many coats of paint do I need?
Two coats is standard for proper coverage and durability. One coat may suffice if you are painting a similar color over an existing finish. Dark colors going over light walls usually need 2-3 coats.
What does 'coverage per gallon' mean?
The area one gallon can paint with a single coat. Most interior latex paints cover 350-400 sqft per gallon on smooth walls. Textured surfaces reduce coverage by 10-15%.
Should I include doors and windows?
Subtract them. A typical interior door takes about 21 sqft of wall space; a standard window about 15 sqft. The calculator subtracts these automatically based on your count.
How much paint for the ceiling?
Multiply room length by width. A 12 x 15 ft ceiling is 180 sqft, so about 0.5 gallons for one coat. Add this separately if you're painting the ceiling.