ENGINEERING CALCULATOR
Duct Airflow Calculator
Calculate airflow from duct dimensions and air velocity.
Formula
Airflow (m³/h) = duct area (m²) × velocity (m/s) × 3,600.
How it works
Circular area = π × diameter² / 4. Rectangular area = width × height. Dimensions are in millimetres.
Limitations
Airflow is at actual duct conditions, not normalised airflow.