Room volume calculator
Volume of a room from its dimensions or floor area.
Fill in the fields and the result will appear here automatically.
Calculates room volume either from length, width and height or from a known floor area and height. With dimensions it also reports the perimeter and wall area, which is what paint and wallpaper estimates start from.
How it works
Formula and logic
Volume V = A·H. Dimensions mode uses A = L·W, perimeter P = 2(L + W) and four-wall area P·H without subtracting openings. Known-area mode returns only V, A and H: floor area alone cannot determine perimeter or walls. Active dimensions are positive and finite; hidden dimensions are ignored. A variable-height space requires an area-weighted mean height for V.
Example
A room 5 × 4 m with a 2.7 m ceiling holds 54 m³.
Fields and units
- How to measure — By room dimensions / By floor area
- Length — m
- Width — m
- Floor area — m²
- Height — m
How to use
- — Choose how you are measuring.
- — Enter the dimensions or the floor area.
- — Enter the ceiling height.
Method and limitations
- Calculation method
- Formula and logic
- Limitation
- Known-area mode returns only V, A and H: floor area alone cannot determine perimeter or walls. A variable-height space requires an area-weighted mean height for V.
FAQ
Why does the area mode not show wall area?
Walls depend on the perimeter, and many different room shapes share one floor area. Without length and width there is nothing to compute it from.
Are doors and windows subtracted?
No. This is the gross figure; openings are handled by the paint and wallpaper calculators.
What is room volume used for?
Ventilation and heating sizing mostly, where the air being moved or warmed is what matters.
Does ceiling shape matter?
Yes. Use a mean height weighted by floor area. In a rectangular room with a linearly sloping ceiling, the mean of its two end heights gives volume; split arbitrary shapes into parts or integrate height. This does not determine sloping wall areas.