Paint Calculator

Estimate gallons of paint for walls, including multiple coats.

Surface area

Number of coats

Coverage per gallon (ft²/gal)

Price per gallon ($)

Paint needed (gal) 3

Total cost ($) 0

Formula: gallons = area × coats ÷ coverage

Step-by-step with your numbers:

1. Values used:

2. Surface area = 400

3. Number of coats = 2

4. Coverage per gallon = 350 ft²/gal

5. Price per gallon = 0 $

7. Paint needed = 3gal

8. Total cost = 0$

Did we solve your problem today?

Find out how many gallons of paint to buy. Measure the total wall area, choose your number of coats, and subtract large openings if you like.

The math behind it

Gallons = total area × number of coats ÷ coverage per gallon, rounded up.

One gallon typically covers ~350 ft² per coat on smooth, primed surfaces (less on rough/porous ones).

400 ft² with 2 coats at 350 ft²/gal → 800 ÷ 350 = 2.3 → 3 gallons.

Do I count doors and windows?

Subtract large openings; for small rooms it's safer to leave them in as extra allowance.