Live tool/tool/air-changes-per-hour-calculator

Air Changes Per Hour Calculator

Estimate room ventilation turnover from airflow and room volume so you can sanity-check airflow targets quickly.

EngineeringHVACReference

Room length

Room width

Ceiling height

Airflow

CFM

Room volume

1,344 ft3

Air changes / hr

14.29

Airflow

320 CFM

One full air change

4.2 min

Rule of thumb

ACH targets vary a lot by use case. This is most useful for rough ventilation comparisons, not code compliance.