Calculators
Room Volume Calculator
Calculate room volume, floor and wall area, and the airflow needed for a chosen number of air changes per hour.
- Runs in your browser
- Nothing uploaded
The tool
Enter your numbers below. Results update as you type, and nothing leaves your browser.
Everything you enter stays on your own machine. Nothing is sent to us or to anyone else, which you can confirm in your browser network tab.
What people use it for
- Sizing an extractor fan or air purifier
- Choosing a dehumidifier or heater
- Estimating paint and flooring together
- Ventilation planning
About this tool
What the Room Volume Calculator does
Room volume is length × width × height. It sizes heating, ventilation and dehumidifiers, and with an air-change rate it gives the airflow a fan must move. Floor and wall areas are useful for flooring and paint at the same time.
Formula
- Volume = length × width × height
- Airflow (CFM) = volume × air changes per hour ÷ 60
- Wall area = 2 × (length + width) × height
Worked example
Using the starting values in the calculator above:
| Input | Value |
|---|---|
| Units | Feet and inches |
| Length | 14 |
| Width | 12 |
| Ceiling height | 9 |
| Air changes per hour | 6 |
| Result | Value |
|---|---|
| Room volume | 1,512.0 |
| Airflow for chosen air changes | 151.2 |
| Floor area | 168.0 |
| Wall area | 468.0 |
How to read the result
Recommended air change rates vary by room use: kitchens, bathrooms and workshops need more than bedrooms.
Air purifiers and fans list airflow in CFM or m³/h; compare that figure with the result.
Quantities are estimates. Check product data sheets and local codes, and confirm with your supplier before ordering.
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Questions
Questions about this tool
The things clients actually want to know — costs, timelines, ownership and what happens after launch.
Multiply length, width and height.
How many times the full volume of air in a room is replaced each hour.
Multiply room volume in cubic feet by ACH, then divide by 60.
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