Paint per Square Foot Calculator
By Vinod Kondeti · Updated
If you already know the surface area, for example from a contractor quote or a plan, this converts it straight into gallons: area × coats ÷ coverage. At 350 ft² per gallon, one gallon covers about 0.0029 gallons per ft² per coat.
How do I measure for a paint per sq ft project?
- Use the square footage calculator to measure walls or fences first.
- Multiply by the number of coats. The calculator does this for you.
- Buy whole gallons for large jobs. Mixing several cans together evens out slight colour differences.
How is the paint per sq ft amount calculated?
- Room walls = 2 × (length + width) × height − doors & windows (+ length × width for the ceiling)
- Gallons = area × coats ÷ coverage per gallon (default 350 ft²)
- To buy = gallons rounded up to whole quarts (4 qt = 1 gal)
- Exterior = perimeter × wall height + gables × ½ × width × height − openings
- Openings = doors × area per door + windows × area per window + other
- Primer (optional) = one coat: area ÷ primer coverage
- Cost = whole gallons × your $/gal (paint + primer)
Paint per sq ft calculator questions
How much paint for 1,000 ft², 2 coats?
2,000 ÷ 350 = 5.71 gal, so 5 gallons + 3 quarts.
How many coats should I plan?
The calculator defaults to 2. Follow the recommendation on your can.
Sources
Estimates only. Use the coverage or bag size printed on your product. Read the paint guide for worked examples.