Construction calculator
Paint Calculator
Estimate paint for walls and ceilings from room dimensions or a known paintable area, with adjustable coats, coverage and container size.
Enter the paint area and calculate.
Paint calculator example
Example: 20 ft × 12 ft room, 8 ft walls, 66 ft² of doors/windows, two coats, and 350 ft² per gallon coverage.
Wall area = 2 × (20 + 12) × 8 = 512 ft²
Net wall area = 512 − 66 = 446 ft²
Two coats = 892 ft²
892 ÷ 350 = 2.55 gallons
Net wall area = 512 − 66 = 446 ft²
Two coats = 892 ft²
892 ÷ 350 = 2.55 gallons
Using 1-gallon containers, this rounds up to 3 gallons.
Should doors and windows be subtracted?
For a more precise estimate, subtract openings that will not be painted. On small jobs, some people leave them in as a practical allowance for touch-ups, absorption and small measurement errors.
How many coats should I plan for?
Two coats are common for many finish applications, but coverage depends on substrate, primer, colour change and paint specification. Enter the number of coats required for your actual project.