Paint quantity calculator
Estimate the amount of paint (in liters) needed to repaint the walls of a room, based on its dimensions, the area of doors/windows to deduct, the paint's coverage, and the number of coats. 100% local calculation.
How it works
The calculation starts by determining the total wall area (room perimeter multiplied by ceiling height), then subtracts the area of doors and windows that won't be painted. This net area is then multiplied by the planned number of coats and divided by the paint's stated coverage (in m² per liter, shown on the can) to get the total volume needed.
Why plan for several coats?
A single coat of paint often lets the original wall's color or imperfections show through, especially when making a significant color change (going from white to a dark color, for example). Two coats are generally recommended for an even, long-lasting finish; a third may be needed for very bright colors or very absorbent surfaces.
Is the coverage shown on the can always reliable?
The coverage stated by the manufacturer (often 10 to 12 m²/L) corresponds to ideal conditions on a smooth, already-prepared wall. A raw, very absorbent, or dark-colored wall to be covered will use more paint than expected: it's better to plan for an extra 10 to 15% margin as a safety buffer, especially so you don't have to interrupt the job for lack of paint.
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