About the Paint Calculator
Paint coverage is printed on every tin, usually 10–12 m² per litre per coat for emulsion. Work out the surface area, deduct doors and windows, multiply by the number of coats and divide by the coverage. This calculator does all of that and converts the answer into tins you can actually buy.
Also known as: how much paint do i need, paint quantity calculator, litres of paint, paint coverage calculator, room paint calculator.
How to use this calculator
- Enter room length, room width, ceiling height, painting and the other fields.
- The result updates instantly as you type — press Calculate (or Enter) at any time.
- Open “Step-by-step” to see how the answer was worked out.
- Use Copy result or Share to save the answer or send a link with your inputs.
Formula
litres = area × coats ÷ coverage per litre
Worked example
Using the values pre-filled in the calculator above:
- Room length = 5 m
- Room width = 4 m
- Ceiling height = 2.4 m
- Painting: Walls only
- Doors = 1
- Windows = 2
- Number of coats = 2
- Coverage per litre = 11 m²
the calculator returns:
- Paint required: 6.98 litres
- 5 litre tins: 2
- 2.5 litre tins: 3
- Area to paint: 38.4 m²
Working
Wall area: 18 m × 2.4 m − 4.8 m² openings = 38.4 m²38.4 m² × 2 coats ÷ 11 m²/L = 6.98 L