How to use this calculator
Enter the total paintable wall area before subtracting openings. Use the manufacturer’s coverage for your surface.
- Enter measurement method, total wall area (m²), area of doors and windows (m²) and review the remaining options.
- Select Calculate or change a value to update the result. Read the result label and units before copying.
- Use Reset to restore the worked starting values.
Formula and method
Surface porosity, application method, and color changes can affect actual coverage.
Worked example
60 m² less 5 m² of openings, two coats at 10 m²/L, plus 10% waste requires 12.1 L.
Questions about paint calculator
Why should I enter product coverage and the number of coats?
Required paint is net surface area times coats, divided by coverage, then increased by the waste allowance. Coverage varies by product and surface. Openings are subtracted from area, so use compatible square-meter and liters-per-coverage conventions shown in the inputs.
What assumptions should I check?
Surface porosity, application method, and color changes can affect actual coverage.
Are my inputs saved?
Calculations run in your browser. We store only tool IDs for favorites and recent tools. A calculation link contains your inputs only when you explicitly choose to copy one.