Calculate the gross and net wall area of a room in m² — minus windows and doors. Suitable for paint, wallpaper or tiles.
Indicative consumption: paint ~8–12 m²/l (1 coat), for wallpaper see the wallpaper calculator, for tiles — the tile calculator.
| Step | Formula |
|---|---|
| Perimeter | 2 × (length + width) |
| Gross area | Perimeter × height |
| Opening area | (window count × W × H) + (door count × W × H) |
| Net area | Gross area − opening area |
The calculator assumes all four walls have the same height (a standard rectangular room).
Yes, if you'll paint them separately or they aren't painted — the net area gives a more accurate paint/wallpaper quantity. For a rough estimate, you can set the window/door count to 0.
The calculator works on a rectangular perimeter. For an irregular room, add up each wall's area separately (length × height) and subtract the opening area manually.
On average, 1 liter of paint covers 8–12 m² (depends on the surface and paint type). For two coats, multiply the consumption by 2.
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