What This Calculates
This calculator finds the airflow (in cubic feet per minute) a fan or ventilation system needs to achieve a target number of full air exchanges per hour in a room — a common HVAC design metric.
The Formula
CFM = (Room Volume × Air Changes per Hour) / 60, where room volume is length × width × height.
For general planning purposes; actual HVAC sizing should also account for duct losses, filters, and static pressure.
Last reviewed August 2026