Paint Coverage Calculator
The tin's coverage assumes a wall you probably do not have.
Work out Paint Coverage. The tin's coverage assumes a wall you probably do not have. Free, with no account and nothing to install.
Paint to buy
3 tins
5.08 litres for 2 coats over 30.5 m²
The coverage printed on a tin is measured on a smooth, sealed, previously painted surface. New plaster drinks a mist coat, textured or porous surfaces take half again, and rollers waste more than brushes — so treat the tin figure as a best case and the coverage here as the number to adjust. Dark over light needs an extra coat regardless of the paint's opacity claims, and strong colours — reds and yellows especially — often need three. Tinted primer in a similar shade saves more time than an extra topcoat does. Doors are deducted at 1.6 m² and windows at 1.5 m², which are typical UK sizes. Deducting openings is worth doing for a room with large glazing and barely matters for one with a single small window.
How the Paint Coverage Calculator works
Paint for a room, with openings deducted and coverage as an input rather than an assumption. The figure on the tin is measured on a smooth, sealed, previously painted surface — which new plaster is not.
Also known as: how much paint for a room · litres of paint per square metre · how many tins do i need · paint for two coats calculator
Frequently asked questions
How much paint do I need for a room?
A typical 4 × 3 m room with 2.4 m ceilings has about 30 m² of wall after deducting a door and a window, which needs roughly 5 litres for two coats at 12 m² per litre.
Why does my paint not go as far as the tin says?
Because tin coverage is measured on a smooth, sealed, previously painted surface. New plaster absorbs a mist coat, textured surfaces take half again, and rollers waste more than brushes.
How many coats do I need?
Two on a similar colour, three going dark over light or with strong reds and yellows. A tinted primer in a similar shade saves more time than an extra topcoat does.
Should I deduct doors and windows?
For large glazing, definitely. For a single small window it changes the answer by a fraction of a litre. This deducts doors at 1.6 m² and windows at 1.5, which are typical sizes.
Is it cheaper to buy a bigger tin?
Almost always per litre, and leftover paint is genuinely useful for touching up. But paint has a shelf life once opened, so buying 10 litres for a 5 litre job mostly buys you storage.
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