Home & DIY
Paint calculator
Estimate wall paint, coverage and cost for a rectangular room.
A clear answer. Here’s how.
Wall area = 2 × (length + width) × height, less the openings you enter. Paint litres = net area × coats ÷ stated coverage, with your extra allowance added. Ceiling excluded. Coverage varies by paint and surface; use the figure on the tin.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Room length (m)
- 4
- Room width (m)
- 3
- Wall height (m)
- 2.4
- Doors and windows area (m²)
- 3
- Number of coats
- 2
- Coverage per litre (m²)
- 10
- Extra allowance (%)
- 10
- Price per litre
- 12
Example result
- Net wall area
- 30.6 m²
- Paint including allowance
- 6.732 litres
- Paint cost estimate
- 80.784