Ventilation calculators and unit converters

Airflow unit conversion

Pressure unit conversion

Power unit conversion

Airflow and air change rate (ACH) calculation

Example rates carried over from the previous site calculator, not code requirements. Enter the approved rate for your project design.

Required airflow = room volume × ACH. Actual ACH = delivered outdoor airflow / volume. The design/code sets ACH; recirculation fans alone do not provide outdoor ventilation.

Kitchen hood extract airflow calculation

Q = area × velocity × 3600. Enter the hood design velocity. This volume calculation alone does not establish capture performance, pressure loss or make-up air.

Fan speed change calculations

Estimate at the same diameter, air density and comparable operation; check manufacturer limits. Unentered fields remain unavailable.

Synchronous motor speed calculation

nₛ = 120 × f / p. This is theoretical synchronous speed, not the fan’s actual RPM; induction motors have slip. Pole count is not inferred from a model name.