Paint quantity calculator
Work out how many litres of paint to buy. Enter your wall area and coats and we will do the rest.
Not sure? Wall length times height, added up for each wall.
Rougher surfaces soak up more paint.
- Coverage used11 m² per litre
How much paint do I need?
Most wall paint covers about 10 to 12 square metres per litre per coat on a smooth, previously painted surface. Bare or textured surfaces like render and brick drink up more, so the coverage drops. Multiply your wall area by the number of coats, then divide by the coverage, and round up to whole cans.
To measure wall area, take the length of each wall, multiply by the height, and add them together. You can leave doors and large windows in for a small safety margin, or subtract them if you want to be precise. It is always better to have a little left over for touch ups than to run out mid wall.
| Surface | Coverage per litre |
|---|---|
| Smooth, painted before | About 11 m² |
| Slightly textured | About 9 m² |
| Rough or bare | About 7 m² |
Working out the budget for a painter instead? See the house painting cost calculator.
Handy gear for this job
The basics for a clean DIY paint job.
- Roller and tray kitView on Amazon AU →
- Angled cutting brushView on Amazon AU →
- Extension pole for rollerView on Amazon AU →
These are Amazon Australia links. If you buy through them we may earn a small commission at no extra cost to you. It never changes the prices we publish.
Common questions
How many litres of paint per square metre?
As a rule of thumb, one litre covers about 11 square metres in one coat on a smooth surface. For two coats over 40 square metres you need roughly 7 to 8 litres.
Should I buy extra paint?
A little extra is wise for touch ups and to keep the same batch colour. Buying a second batch later can show a slight colour difference.
Does a primer count as a coat?
Treat primer separately. If you are priming bare or patched areas, buy primer on top of your top coat litres rather than counting it in the same total.
These figures are estimates to help you plan and sense check quotes. They are not a quote. Site access, materials, finish and your location all move the final price. Always get two or three written quotes.
Know a fair price before you call
Browse the rest of the free calculators and hiring guides, or read the cost guides on the blog.