Free · Materials specifications calculators 🏗️

Room Volume & Required Airflow Calculator

Convert a chosen air-change target into a nominal volumetric airflow.

  • Formula & worked example
  • Private in your browser
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Edit a calculated value to solve backwards, or lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Private by default

Inputs and results stay in this browser tab. Bookify does not upload or store the values you enter.

Formula and method

A room 5 × 4 × 3 meters has volume 60 m³. A target of three air changes per hour corresponds to 180 m³/hour, or 0.05 m³/second.

Required airflow per hour = room volume × air changes per hour

Worked example

Enter these known values and leave the other values blank.

Length
5 m
Width
4 m
Ceiling height
3 m
Air changes per hour (ACH)
3
Floor area
20 m²
Volume
60 m³
Required airflow
105.94 CFM
Airflow rate in other units
0.05 m³/s

Assumptions and limitations

  • No. You supply the target air changes per hour. Outdoor-air requirements, air distribution, filtration, pressure losses and equipment performance are separate design considerations.
  • Use consistent units and project-specific dimensions, density and prices. This geometric estimate does not add quantities that are absent from the formula.

Common questions

Does the calculator select a required ventilation rate?

No. You supply the target air changes per hour. Outdoor-air requirements, air distribution, filtration, pressure losses and equipment performance are separate design considerations.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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