Example 1 — Standard room
- Length: 5 m
- Width: 4 m
- Height: 2.5 m
Volume: 50 m³
This is a classic example of a residential room with a typical ceiling height.
Room volume
Enter length, width, and height — we’ll get room volume for ventilation, heating, cooling, and interior planning.
Room volume is how much space is inside — handy for air changes, heating load, and comparing rooms with the same floor area but different ceiling heights. Next: heating power, wall area.
Results
Enter data and click Calculate.
How the results are calculated
Volume = max(0, length×width×height − deducted volume) × repeat count. The suggested heating power is ~40 W/m³, multiplied by a room-type factor (bathroom ×1.2, attic ×1.1).
How to use this calculator
- Enter the room length, width, and height.
- Read the result as volume in cubic metres.
- If you are comparing several rooms, calculate each one separately.
- Use the volume as a supporting metric for heating, ventilation, and technical planning.
Example scenarios
Example 2 — Higher living room
- Length: 6 m
- Width: 5 m
- Height: 2.8 m
Volume: 84 m³
With a higher ceiling, floor area alone is no longer enough to fully compare interiors.
Example 3 — Small study room
- Length: 3.5 m
- Width: 3 m
- Height: 2.6 m
Volume: 27.3 m³
This is a good example of how a small room can have a noticeably different usable volume than floor area alone might suggest.
FAQ
What exactly is “room volume” in this calculator?
Interior volume — how much space is in the room (in the volume unit from the header).
How do you calculate it?
Usually length × width × height. For a rectangular room, that’s enough.
How is that different from area?
Area is the floor (or a wall). Volume adds height — two rooms with the same floor area can hold very different amounts of air.
Why would I need volume?
Ventilation estimates, heating, cooling, and comparing how much space is really inside.
Does it matter for heating?
Yes — more air to warm usually means a higher heating load.
What about slopes and odd shapes?
They change the number. Split into simpler solids and add — or deduct what isn’t there.
Where do people usually go wrong?
Mixing square units with cubic ones, or using rough height instead of finished ceiling height.
What should I calculate next?
Most often heating power — or another air-change / comfort number.