How it is calculated
Add alcoves and box-outs to the openings or to the area yourself. The ceiling is not in this formula.
Walls = 2 × (length + width) × height − openings
Where the numbers come from
- Length — unit in the field: m
- Width — unit in the field: m
- Height — unit in the field: m
- Openings — unit in the field: m²
Example
A room of 5×4 m, height 2,7 m, and openings of 2 m² gives 2 × (5 + 4) × 2,7 − 2 = 46,6 m².
Questions
The room is not a rectangle?
Break it into rectangles, or enter a perimeter you already know as length plus width, and pick a pair that adds up.
Are the openings in square meters?
Yes. A window of 1,2×1,5 m is 1,8 m².
Do you need extra?
For paint and plaster the waste lives in their own calculators. Here you get the bare area.