Paint Calculator - How Much Emulsion Do You Need? (UK)
Pop in the wall area you're painting and how many coats you're putting on, and this works out how much emulsion you need - in litres and in tubs to buy.
Interested? Then → Quotato for Painters & Decorators · More advice on the Blog & Chips guides.
How to use this calculator
Measure the total wall area in square metres (length times height for each wall, added up) and enter how many coats (two is standard). You'll get the litres of emulsion and the number of 10L tubs to buy.
How we calculate this
- We multiply your wall area by the number of coats, then divide by the paint's coverage to get litres.
- We use 11 m² per litre per coat, typical for UK matt emulsion on prepared, previously painted walls.
- We size the order into 10L tubs - fresh or porous plaster drinks more, so round generously on bare walls.
Worked example
30 m² of wall with two coats = 60 m² painted. Divide by 11 m²/litre and you need ~5.45 litres - one 10L tub with a bit spare. Three coats on a strong colour pushes it to ~8.2 litres, still one 10L tub but closer to the line.
UK notes & gotchas
- 11 m²/litre/coat suits standard UK matt emulsion on sound, previously painted walls - silk and one-coat paints differ.
- New/bare plaster needs a thinned mist coat first, which uses extra paint - add a tub for bare walls.
- Emulsion comes in 2.5L, 5L and 10L tubs; we order in 10L as best value but you can split across smaller tins.
FAQ
Does this include the ceiling?
No - wall area only. Add the ceiling's area (length times width) or run the calculator again for it.
How many coats should I use?
Two is standard on previously painted walls; three for a big colour change, plus a mist coat on bare plaster.
What coverage does it assume?
11 m² per litre per coat, typical for UK matt emulsion. Textured surfaces and strong colours reduce coverage.
Why does it order 10L tubs?
Best value for trade-sized rooms. For a small job buy a 5L or 2.5L - the litre figure tells you what to aim for.
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