Paint quantity calculator
Measure a rectangular room, subtract the total door and window area, and enter your chosen number of coats and product coverage.
Enter your measurements, then calculate.
Method and limitations
Walls = 2 × (length + width) × height − openings; ceiling = length × width. Litres = selected area × coats ÷ coverage in m²/L. Openings apply only to walls. Enter the coats and coverage from your product instructions: no recommended coat count or coverage is assumed. The estimate excludes trim, surface absorption and application losses. NIST Appendix C: 1 ft = 0.3048 m; 1 ft² = 0.09290304 m²; 1 US liquid gallon = 3.785411784 L. Gallons shown are US, including in Canada. NIST: https://www.nist.gov/system/files/documents/2023/01/30/appc-23-HB44.pdf