About this calculator
Paint for the outside of a house, including triangular gable ends, with an allowance for rough surfaces that soak up more paint.
How it’s calculated
Area = perimeter × eaves height + ½ × gable width × gable height for each gable − openings. Texture multiplies the area. Paint = area × coats ÷ coverage.
Worked example
With these inputs:
- House perimeter
- 40 m
- Wall height (eaves)
- 5 m
- Gable ends
- 2
- Gable width
- 8 m
- Gable height (eaves to peak)
- 2.5 m
- Doors and windows area
- 12 m²
- Surface
- Smooth (siding, render)
- Coats
- 2
- Coverage (m² per litre)
- 10
the result is:
- Paint needed
- 41.6 L
- Wall area (net)
- 208 m²
- Texture-adjusted area
- 208 m²
Tips from the trade
- Soffits and fascias are extra. Add them as their own line in your job.
- Spraying uses 20–30% more than rolling because of overspray.
Results are estimates for planning and pricing. Check quantities against your drawings, the manufacturer’s data and the Building Regulations before ordering.