Wall paint calculator
Calculate how many liters of paint and cans you need from area and number of coats.
Coverage varies by paint and surface (10–14 m²/L is common). Check the package.
How the calculation works
Paint quantity depends on the area, the number of coats and the paint's coverage (m² per liter, shown on the can).
liters = (area × coats) ÷ coverage
For the area, add the walls (perimeter × ceiling height) and the ceiling, then subtract large doors and windows.
Step-by-step example
40 m² of wall, 2 coats, paint covering 10 m²/L per coat:
- Liters: (40 × 2) ÷ 10 = 8 liters
Examples
- A 12 m² bedroom wall, 2 coats, 11 m²/L coverage: ~2.2 L.
- Strong color over a light wall: count 3 coats instead of 2.
Frequently asked questions
How many coats do I need?
Usually 2 coats. Strong colors or big color changes may need 3.
Where is the paint coverage?
On the can, in m² per liter (or per coat). It varies a lot — use your paint's figure.
Do I need primer or sealer first?
New or very porous walls need a sealer, which cuts paint use. This estimate covers only the finish coat.
Why did the paint cover less than the label says?
Because the printed coverage assumes ideal conditions. Unsealed new surfaces and textured walls consume far more.
Should I subtract doors and windows?
Usually not for small openings — the surplus covers spillage and touch-ups.
How many coats do I need?
Two is standard; three or more for light-over-dark or strong pigments like red and yellow.
Can I buy the paint in separate batches?
It is risky — shades vary between production batches and the difference shows on the finished wall.
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Updated on June 17, 2026 · by Rafael Rossi · Methodology & sources