Free Tool · New 2026
Paint Calculator: How Much Paint Do I Need?
Enter your wall dimensions and number of coats to calculate exactly how many liters of paint to buy, based on standard coverage rates.
Want an exact number, not an estimate?
This calculator gives a strong planning estimate. For an exact, guaranteed figure, our engineers confirm everything during a free site survey.
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The paint calculation formula
- Paintable area = (Total wall length × height) − door/window area
- Paint needed (liters) = (Paintable area × number of coats) ÷ coverage rate per liter
Coverage rate varies by paint type and wall surface — budget emulsion paints often cover less per liter than premium paints, and rough or previously unpainted walls absorb more paint on the first coat. Check your specific paint tin's stated coverage rate rather than assuming a generic number for an exact figure.
Useful beyond just walls
This same formula works for ceilings (measure length × width instead of length × height) and for exterior villa walls, gates and boundary walls — just measure the relevant surface area and deduct any doors, windows or gates.
Planning a bigger renovation alongside painting?
If you're repainting as part of a wider renovation that also involves networking, smart home wiring or CCTV, it's worth planning cabling routes before the paint goes on.
Frequently asked questions
Most standard emulsion paints cover 8-12 m² per liter per coat, but always check the manufacturer's stated coverage on the tin, since formulations vary.
Two coats is standard for most walls, especially when changing color significantly or painting over a darker existing color - a single coat often leaves patchy, uneven coverage.
Yes, subtract the combined area of doors and windows so you don't overbuy paint - this calculator has a field specifically for that deduction.
Yes, the same length x height formula applies - just use exterior-grade weatherproof paint and note that exterior paint coverage rates can differ from interior paint.