How this calculator works
Find out how many gallons of paint you need based on room size, coats, and coverage. Values are processed instantly on this device, with checks for missing values and invalid operations.
Gallons: (wall_area - openings) * coats / coverage_per_gallon
Worked example
Enter realistic values in each labeled field, select Run tool, and review both the primary answer and supporting reasoning. Use Reset before trying another scenario.
Frequently asked questions
What does the Paint Calculator do?
Find out how many gallons of paint you need based on room size, coats, and coverage.
Are my values stored?
No. The calculation runs locally in your browser and the values are not submitted to us.
Can I rely on this result?
Use this as an informational estimate. Check measurements and source values before acting on the result.