Stable Numbers
Paint Calculator
Estimate how many litres of paint you need for a room. Enter room size, doors and windows, number of coats and your paint’s coverage. The tool adjusts for ceiling painting and a small wastage margin, and suggests tins by size.
Doors and windows
Default door area is editable below.
Default window area is editable below.
UK typical door around 1.9–2.2 m².
Check your tin. 10–14 m²/L is common for emulsions.
To allow for touch-ups and absorption.
Tin sizes
Set the sizes you can buy. We show a few sensible combinations.
Area summary
- Wall area (all walls):
- Ceiling area:
- Openings excluded:
- Paintable area (per coat):
Paint needed
- Coats:
- Coverage:
- Wastage:
- Total litres needed:
Tin suggestions
Closest simple combinations that meet or slightly exceed your litres required.
- → L total
- Adjust tin sizes to see suggestions.
Results are guides only. Coverage varies by surface and paint brand.
About this calculator
This paint calculator totals the wall area from your room perimeter and height, subtracts doors and windows, and optionally adds the ceiling. It multiplies by the number of coats, divides by your paint’s coverage per litre and adds a small wastage percentage to give a sensible buying estimate.
Use metres if you can for straightforward square-metre outputs. If you prefer feet and inches, switch to feet and the calculator converts behind the scenes. The tin suggestions show simple combinations of the sizes you can buy that cover the requirement with minimal leftover.
Explore more in the calculators hub.