Work out how many litres a room needs from its wall area, the number of coats and the paint’s spread rate — with doors and windows taken off.
Bare plasterboard, render or dark colours often need a sealer/undercoat plus extra topcoat, so allow more. Buy a little over rather than run out mid-wall.
traqR keeps your paint and material quantities on the job card so estimates flow into the quote and the shopping list.
Start free trialAdd up the wall area — perimeter times height — then subtract the doors and windows you won’t paint.
Two coats doubles the area to be covered. Bare or strongly coloured surfaces may need an undercoat plus two topcoats.
The paint tin’s coverage (m² per litre) turns the total area into litres. Always round up to the next tin size.
Work out the wall area (perimeter × height, less doors and windows), multiply by the number of coats, then divide by the paint’s spread rate. A typical 5 × 4 m room at 2.7 m high has about 45 m² of wall, needing roughly 7.5 litres for two coats at 12 m²/L.
It’s how far a litre of paint goes, printed on the tin as square metres per litre — usually 10–16 m²/L. Rough, porous or textured surfaces use more paint (lower coverage), and the first coat on bare material always soaks in more.
Two topcoats is standard for a good, even finish. Painting over bare plasterboard, patched areas or a very different colour usually also needs a sealer or undercoat first, so budget for the extra product.
Yes. Buy to the next tin size rather than the exact litres. Running out mid-wall risks a visible join, and a slightly different batch may not match — a little spare paint is also handy for touch-ups later.
This calculator estimates wall paint for a rectangular room and is a general guide. Actual quantities vary with surface type, porosity, colour change, application method and the specific product. Check the tin’s coverage and allow extra for undercoats and touch-ups.
traqR keeps paint and material quantities on the job card so estimates flow into the quote and shopping list. Try it free for 14 days.