JUST ENOUGH PAINT.
Less guessing. Less waste.

How much paint do I need? Find out in seconds.

Wondering how much paint you need? Get a quick estimate for your walls and ceiling — without buying more than you need.

Free paint calculator · No signup required
Your paint calculator

Let's measure your space.

Just a few details and we'll do the maths for you.

m
m
m
A little more detail Optional, but more accurate
m²/L
Assumes each door is 1.8 m², each window is 1.5 m², and 10% extra paint for touch-ups and waste. Update coverage using your paint tin's label.
Why just enough paint?

Paint smart. Waste less.

Less time calculating, less money wasted, and more confidence at the paint counter.

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Simple room measurements

Enter the length, width and height of your room. We'll work out the surface area automatically.

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Accounts for the details

Subtract doors and windows, add the ceiling and choose how many coats you'll apply.

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Buy the right quantity

See a paint estimate in litres and a practical suggestion for common tin sizes.

The simple science

How do we calculate it?

We calculate your wall area from the room perimeter multiplied by wall height. Then we subtract an allowance for doors and windows and add your ceiling if selected.

  1. Calculate the paintable surface area.
  2. Multiply by the number of coats.
  3. Divide by the coverage on the paint tin.
  4. Add a 10% allowance for waste and touch-ups.

Our suggested tin combinations use common 1 L, 2.5 L, 5 L and 10 L sizes, but the sizes actually sold vary by brand.

Good to know

Frequently asked questions

How much does one litre of paint cover?

A commonly used estimate for interior wall paint is around 10–12 m² per litre per coat. Actual coverage depends on the product, surface and method, so check the tin.

Should I buy extra paint?

We include a 10% allowance for touch-ups and waste. Highly absorbent walls, new plaster or strong colour changes may need additional paint or primer.

Does this calculate paint for all four walls?

Yes. It assumes a rectangular room and includes all four walls. For irregular rooms, calculate each section separately and add the results.

Does it work in feet?

Yes. Switch the measurement unit to feet. Your result will still be shown in litres.

More painting help

Calculate paint for any project

Painting a whole room?

Measure four walls, subtract windows and doors, and estimate how many litres to buy.

Room paint guide →