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Work out how much paint to buy. Enter the area, the number of coats and the product’s stated coverage, and the calculator returns total litres and a suggested combination of tin sizes, with an optional primer coat included.
How to use
- Enter the total area to be painted in square metres, deducting large openings.
- Set the number of coats. Two is standard for emulsion on a prepared surface.
- Enter the coverage from the tin, usually given in m² per litre.
- Add a wastage allowance for rollers, trays and touching up.
- Switch the primer coat on for bare plaster, bare timber or a strong colour change.
Notes
- Most emulsions cover 10–13m² per litre per coat on a sealed surface. Bare plaster absorbs far more on the first coat.
- A mist coat — emulsion thinned with water — is needed on new plaster before the finish coats, and is not the same as a primer.
- Dark colours and strong reds usually need an extra coat regardless of the coverage figure.
- Buy the full quantity in one go so all tins come from the same batch.
FAQs
How much paint do I need for a room?
Measure the wall area, subtract windows and doors, then divide by the coverage on the tin and multiply by the number of coats. As a rough guide, a typical 4 × 4m room with 2.4m ceilings needs around 5 litres for two coats on the walls.
How many coats of paint on new plaster?
A thinned mist coat first, then two full coats. Skipping the mist coat is the most common cause of paint peeling off fresh plaster.
Does the ceiling need different paint?
Not necessarily, but a dedicated ceiling paint tends to be less prone to dripping and dries to a flatter finish that hides unevenness better under direct light.
Need more than an estimate?
These tools give you a reliable starting figure. When you’re ready to turn it into a costed, fixed-scope proposal, our team works across London, Dubai and Cairo on architecture, interior design and turnkey delivery.
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