Paint Calculator
Work out how many litres of paint you need from your wall dimensions, coats and coverage rate.
How it works
Paintable area is the gross wall area (width × height × number of walls) minus any doors and windows. That area is multiplied by the number of coats, divided by the paint’s coverage rate, then increased by your wastage allowance to arrive at a practical litres figure.
Litres = (Paintable Area × Coats ÷ Coverage) × (1 + Wastage %)
Worked example
A 4m × 2.4m wall, 2 coats, 16 m²/L coverage, no deductions, 10% wastage:
- Area
- 4 × 2.4 = 9.6 m²
- Area × coats ÷ coverage
- 9.6 × 2 ÷ 16 = 1.2 L
- With 10% wastage
- 1.2 × 1.1 ≈ 1.32 L
Frequently asked questions
Check the tin — most interior wall paints cover 10-16 m² per litre per coat, but it varies by brand, paint type and the surface you're painting (a rough or previously-unpainted surface soaks up more). Use the figure printed on your specific product for the most accurate result.