Duct Air Velocity Calculator

Calculate air velocity from CFM and duct size. Free, instant.

How to Use Duct Air Velocity Calculator

1

Enter airflow in CFM.

2

Enter duct diameter.

3

Get air velocity in ft/min.

Frequently Asked Questions

What is ideal duct velocity?

Main ducts: 600–900 FPM. Branch ducts: 400–600 FPM.