Paint Calculator: How Many Gallons for a Room?

Paint Calculator

Enter your room’s length, width and ceiling height. We’ll subtract doors and windows and tell you how many gallons (and quarts) to buy for two coats.

Updated November 4, 2026 · For informational use

How much paint for my room?

Measure in feet. Standard US ceilings are 8 feet.

A standard door is about 21 sq ft (3 × 7 ft) and a window about 15 sq ft. Most paint labels say 350–400 sq ft per gallon; textured or porous walls, dark-to-light color changes and fresh drywall need more.

How much does a gallon of paint cover?

One gallon covers about 350–400 sq ft with one coat on smooth walls. We use 350 to be safe. Most rooms need two coats, so a gallon really covers about 175 sq ft of wall.

*After subtracting 1 door and 2 windows. More sizes are in our guide.
Room (8 ft ceiling)	Wall area*	Two coats
10 × 10	269 sq ft	2 gallons
12 × 12	333 sq ft	2 gallons
12 × 14	365 sq ft	2 gallons + 1 quart
14 × 16	429 sq ft	2 gallons + 2 quarts

Full chart, ceilings and tips: how much paint for a room. Need floor area too? Use the square footage calculator.

Paint Calculator FAQs

How many gallons of paint for a 12x12 room?

About 2 gallons for two coats on the walls of a 12 × 12 room with 8-foot ceilings, one door and two windows. Add about 1 gallon if you’re also painting the ceiling.

How much paint for a 10x10 room?

About 1½ gallons for two coats, so buy 2 gallons (or 1 gallon + 2 quarts).

Is one gallon of paint enough for a bedroom?

Usually only for one coat in a small bedroom. Most bedrooms need 2 gallons for two coats.

Should I buy quarts or gallons?

A gallon usually costs about the same as 2–3 quarts, so if you need more than half a gallon extra, buy another gallon. Keep leftover paint for touch-ups.