Home & DIY
How much paint do you need for a wall?
Liters of paint needed from square meters, coats and coverage — with total cost.
Quick answer
Litres needed = (area m² × number of coats) ÷ coverage per litre. A 40 m² wall with 2 coats and 10 m²/L coverage: (40 × 2) ÷ 10 = 8 litres. Most wall paints cover 8–12 m² per litre per coat.
Paint needed
8 liters
- Suggested cans
- 4 × 2.5 L or 2 × 5 L
Typical wall paint coverage is 8–12 m² per liter per coat. On new or very absorbent surfaces plan an extra coat.
How it works
Buy slightly more than calculated — touch-ups and roller absorption add 5–10%. On new plaster or very absorbent surfaces, plan an extra coat or use primer first; coverage drops on rough or dark surfaces.
Match the tin yield in advanced settings, then round up to shop can sizes (2.5 L, 5 L, 10 L). A roller and brush kit sized to your ceiling height beats buying extra litres from bad technique; lay painter’s tape on trim and spread a drop cloth before you open the first can of interior wall paint.
Some colours ignore the arithmetic above, and it is not about the surface. Strong reds, oranges and deep yellows are made with pigments that are physically transparent, so they can need three or four coats where a beige needs two — you are not covering badly, you are looking at the wall through the paint. The fix is not more topcoat: have the primer tinted to a mid-grey, or to roughly half the strength of your colour, and the same tin then covers in two. Ask when you buy — most mixing counters do it at no cost, and it is cheaper than the extra litres.
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Frequently asked questions
How many coats of paint on a new wall?+
Typically primer + 2 finish coats on new plaster. A single coat over an existing similar colour may suffice for refresh jobs. Dark-to-light colour jumps on new plaster almost always need a dedicated primer or fixative coat before the finish — the calculator sizes finish coats only.
Does ceiling paint differ from wall paint?+
Ceiling paint is thicker and splatters less overhead. Coverage is similar but application is slower. Count ceiling m² in total area — a 4×5 m room with 2.7 m ceilings adds roughly 27 m² of ceiling to your wall total.
Matte vs washable paint — same coverage?+
Coverage is similar per litre, but washable (satin) paints often need an extra coat on dark-to-light colour changes. Check the tin label for exact m²/L — premium washable lines sometimes cover more per coat than budget mattes, which changes your litre count.
How do I subtract doors and windows?+
Measure wall area as length × height per wall, subtract openings, or use room perimeter × height minus 15–20% as a quick estimate for standard rooms. A standard door is ~2 m² and a window ~1.5 m² — subtract each opening you will not paint.
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