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Paint Calculator

Liters needed from wall area, coats and coverage.

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The paint calculator estimates the amount of paint required from the paintable surface area, number of coats and the coverage rate you enter. It reports the requirement in liters and also converts that quantity to US gallons.

How it works

Enter the net wall or surface area in square meters, the number of coats and the expected coverage in square meters per liter. The calculator multiplies area by coats, divides by the coverage rate and then converts liters to US gallons.

The formula

Paint required (L) = area (m²) × number of coats ÷ coverage (m²/L). US gallons = liters ÷ 3.785411784.

Area should represent the surface that will actually be painted. Coats is the number of complete applications. Coverage is editable and the calculator defaults to 10 m²/L. Real coverage depends on paint type, substrate, porosity, application method and manufacturer instructions. The calculator does not automatically add a waste allowance.

Worked example

For 100 m², 2 coats and coverage of 10 m²/L, paint required = 100 × 2 ÷ 10 = 20 L. That is about 5.3 US gallons.

This is a material-quantity estimate. Confirm actual coverage, coat requirements, primer needs and application instructions on the product technical data or manufacturer label.

Frequently asked questions

Should doors and windows be deducted from the area?

Use the net paintable area. If doors, windows or other openings will not be painted, subtract them before entering the area.

Is 10 m²/L a universal coverage rate?

No. It is the editable default in this calculator. Use the coverage stated for the actual coating and surface whenever available.

Does the result include paint waste?

No. The result follows the entered area, coats and coverage only. Add any project-specific allowance separately.

Last content reviewAugust 8, 2026
Editorial reviewHe-Sab Editorial Review

Sources and references

These sources are used to verify terminology, formulas, and information related to this calculator.