Paint Coverage Calculator
Estimate how much paint you need from area, coats and coverage.
An estimate. Coverage depends on the paint, colour and how porous or textured the surface is — always check the tin and keep a little spare.
How the estimate works
Start with the area you are painting and subtract large openings like doors and windows to get the net area. Multiply by the number of coats, then divide by the paint's coverage rate to get the volume you need.
Paint = (area − openings) × coats ÷ coverage
Coverage is the figure that varies most. Smooth, sealed walls go further; bare plaster, masonry and textured surfaces soak up more, so the first coat especially can use extra. When in doubt, round up — a spare tin is cheaper than a second trip.
A room with 60 m² of wall, minus 4 m² of doors and windows, painted in 2 coats at 11 m²/L needs about 10.2 litres — so five 2.5-litre tins, leaving a little spare for touch-ups.
Getting a smooth result
Running out halfway up a wall is the classic decorating mistake — colour and sheen can differ subtly between batches, so a mid-job top-up rarely matches perfectly. Estimating the whole job up front, with a margin, avoids that.
Practical tips
- Prime the tricky bits. Bare or patched surfaces drink paint; a primer or mist coat evens out absorption and saves topcoat.
- Buy in one batch. Same colour, same batch number, for a consistent finish.
- Keep the leftovers. Note the colour code and store a sealed tin for future touch-ups.