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Paint Calculator

Estimate how many litres of paint you need for a room's walls (and ceiling), allowing for doors, windows and number of coats.

Room length (m)

Room width (m)

Wall height (m)

Doors

Windows

Paint ceiling too?

Coats

Coverage (m² per litre)

Tin size (litres)

Area to paint—

Paint needed—

Tins—

Door deducted as 1.9 m², window as 1.5 m² – adjust if yours are very different. Use the coverage printed on your tin; new plaster and dark-to-light colour changes take more.

How it works

Wall area = perimeter (2 × (length + width)) × height, minus doors and windows. The ceiling is length × width. Litres = area × coats ÷ coverage per litre.

Coverage varies between products and surfaces, so always check the figure on the tin. Fresh plaster usually needs a diluted mist coat first, which uses more paint.

FAQs

How many coats of paint do I need?

Two is typical for walls. A strong colour change or new plaster may need more.