Paint Coverage Calculator — How Much Paint Do I Need?
Wall area minus openings, times coats, divided by real coverage (≈10 m²/L emulsion) — with a 10% wastage allowance baked in.
Quick answer: Enter room dimensions, doors and windows, and coats — get the exact paint litres (and US gallons) you need using real coverage rates. Free, instant, private; stops you over-buying tins.
–Litres needed
–US gallons
–Net wall area
How to use
- Enter room length, width and ceiling height.
- Count doors and windows (or adjust the defaults).
- Set coats and your paint's coverage (printed on the tin); read litres + gallons instantly.
About this tool
Paint tins state coverage per litre (typically 10–13 m²/L for wall emulsion, less for rough surfaces). The tool computes net wall area from perimeter × height minus doors (≈1.9 m² each) and windows (≈1.5 m² each), multiplies by coats, divides by your tin's coverage and adds 10% cutting/patching allowance — the same math professional decorators use for estimates.
FAQ
What coverage should I use?
Check the tin: most emulsions are 10–13 m²/L. Textured or dark walls: use 8 and add a coat.
Should I paint the ceiling too?
Add its area (length × width) as an extra surface if using the same product — or use our area converter for odd shapes.
Why 10% extra?
Cutting-in, roller splash and touch-ups always consume more than flat-area math suggests.