Useful Tools / ACH Calculator

ACH Calculator

Calculate air changes per hour and required airflow.

Length (m)

Width (m)

Height (m)

Airflow (m³/h)

Target ACH

Results

Example: air changes in a room

For a 6 × 5 × 2.7 m room, volume is 81 m³. If supply airflow is 486 m³/h, the result is 6 ACH. At an 8 ACH target, required airflow would be 648 m³/h. ACH alone does not show how much air comes from outdoors.

Formula and limitations

ACH = airflow (m³/h) / volume (m³). ACH does not necessarily equal fresh outdoor-air changes.

This tool provides educational estimates only. Verify design and safety requirements with a qualified professional.

Further reading: Reference source ↗. Explore other AirAlign Useful Tools.