๐จ Paint Coverage Calculator
Enter the wall area, the area of openings like doors and windows, how many coats you'll apply, and the coverage per liter of paint, and this tool calculates the total amount of paint you need in liters. Useful for DIY wall painting or estimating how much paint to buy ahead of time.
How to use
- Enter the total area of the walls you're painting.
- Enter the area of parts you won't paint, like doors and windows (openings).
- Enter the number of coats and the coverage per liter of the paint you're using โ the amount of paint needed is calculated automatically.
How the calculation works
This tool works out how much paint you need from the wall area, the area of windows and doors, the number of coats and the coverage per litre. Area to paint = wall area โ openings (windows, doors) Total area = area to paint ร coats Paint needed (L) = total area รท coverage per litre The coverage per litre is printed on the tin; typical water-based paints cover about 8โ12 mยฒ per litre per coat. Work out each wall as width ร ceiling height and add them up.
Worked example
Walls 30 mยฒ, windows and door 3 mยฒ, 2 coats, 10 mยฒ per litre Area to paint: 30 โ 3 = 27 mยฒ Total area: 27 ร 2 = 54 mยฒ Paint needed: 54 รท 10 = 5.4 litres Allowing about 10% extra for unevenness and absorption, around 6 litres is a safe amount.
Things to be aware of
- Porous surfaces such as concrete or bare wood absorb paint, so coverage is lower than stated.
- A big change of colour, especially dark to light, may need a third coat.
- As a guide, the four walls of a 2.7 m ร 3.6 m room with a 2.4 m ceiling come to about 30 mยฒ.
FAQ
Where can I find the "coverage per liter" value?
Check the paint can or product packaging for the coverage estimate. Typical water-based paints cover roughly 8โ12 mยฒ per liter.
Why does the number of coats matter?
Depending on the base color and paint type, a single coat often leaves uneven coverage, so two coats are commonly recommended. The paint needed scales directly with the number of coats.
Should I buy more than the calculated amount?
Yes, it's a good idea to buy about 10% more than the calculated amount to account for uneven coverage and absorption loss.