Example: Duct diameter: 10 in · Air velocity: 700 ft/min → Airflow: 382 CFM.
Duct area: 0.55 sq ft
Frequently asked questions
How do I calculate airflow? Enter your numbers above and the result updates instantly. For example: Duct diameter: 10 in · Air velocity: 700 ft/min → Airflow: 382 CFM.
Is this Airflow Calculator free? Yes — completely free with no sign-up or paywall. It runs entirely in your browser and keeps working offline; the numbers you enter never leave your device.
How accurate is it? It uses the standard published formula for airflow. Results are estimates for planning — not financial, tax, medical, engineering, or legal advice.