Paint Calculator
Estimate how much paint you need for interior walls, exterior walls, or ceilings. Add coats, coverage rate, and optional tin counts.
Measurements
Defaults to per tin when tin size is set. Switch to per litre for decanted quotes.
How this is calculated
Wall area = wall width × wall height.
Paint needed = (area × coats ÷ coverage per litre) × (1 + wastage ÷ 100).
Tins = paint litres ÷ tin size, rounded up (when tin size is provided).
Typical emulsion coverage is about 10–12 m²/L per coat on smooth surfaces — use the figure on your product label.
Related reading
Estimates only — coverage varies by surface texture, porosity, and product. Always check the tin label and buy slightly extra.