Room paint estimator

Calculate the surface, then use your product coverage.

Wall area = 2 × (length + width) × height. Add length × width if painting the ceiling. Subtract the total opening area once, then multiply by coats and divide by the coverage per liter or U.S. liquid gallon. Multiply by (1 + extra percentage / 100). Divide by the selected container size and round up to whole containers.

Example: a 5 m × 4 m room, 2.5 m high, has 45 m² of walls. Excluding 4 m² leaves 41 m². Two coats at an illustrative 10 m²/L need 8.2 L; adding 10% gives 9.02 L. Four 2.5 L containers provide 10 L. A product with different coverage changes that answer.

Deduct only areas you do not intend to paint. Windows, doors, trim, surface porosity, texture, color changes and application technique affect actual needs. Follow the product instructions for coverage, coats and preparation. This is a quantity estimate, not a guarantee that a purchase is sufficient. U.S. volume means liquid gallons, not Imperial gallons.