Paint Calculator
Enter your room dimensions and number of coats, and this paint calculator estimates the wall area and how many gallons to buy.
One gallon covers about 350 square feet per coat; most walls need two coats.
Enter your measurements
Paint you need
3gallons
covers 384 ft² × 2 coats
💡 About 3 gallons. Buy in gallons over quarts, it's cheaper per square foot and gives you touch-up paint.
3
gallons to buy
incl. waste
$105
Est. cost
@ ~$35/gallon
384 ft²
Area
wall
- Wall area
- 384 ft²
- Area × 2 coats
- 768 ft²
- Coverage per gallon
- 350 ft²
- gallons to buy (incl. waste)
- 3
The 2-minute guide
Two coats is normal
A single coat almost never covers evenly, especially over a color change or fresh drywall. Plan for two coats, this calculator defaults to it.
Doesn't subtract doors and windows
For simplicity this estimates full wall area. Big windows or doors mean you'll use a little less, so round down if a room is mostly glass.
Frequently asked questions
How much does a gallon of paint cover?
About 350 square feet per coat for most interior wall paint. Rough or porous surfaces cover less.
How many gallons of paint for a 12x12 room?
A 12×12 room with 8 ft walls is about 384 ft² of wall. Two coats is ~768 ft², which is a little over 2 gallons, so buy 3 gallons (or 2 gallons plus a quart) to avoid running short.