How this calculator works
This rectangular-wall estimate assumes all walls share the entered dimensions. Subtract the combined area of doors and windows if desired. Coverage varies by paint, surface and application; use the product coverage and consider purchase sizes separately.
The formula
Area = length × height × walls − openings
Liters = area × coats / coverageA quick example
Four walls 4 m wide and 2.5 m tall have 40 m². Two coats at 10 m²/L need 8 L before exclusions.
How to use this calculator
- Enter the labeled values, using a decimal point for fractions.
- Check the units and assumptions.
- Calculate, review the result and copy it if needed.
A few common questions
How is this result calculated?
Area = length × height × walls − openings
Liters = area × coats / coverage
What assumptions should I check?
This rectangular-wall estimate assumes all walls share the entered dimensions. Subtract the combined area of doors and windows if desired. Coverage varies by paint, surface and application; use the product coverage and consider purchase sizes separately.
Can I see a worked example?
Four walls 4 m wide and 2.5 m tall have 40 m². Two coats at 10 m²/L need 8 L before exclusions.