Gas Velocity from Mass Flow Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 26, 2026Gas Velocity from Mass Flow Calculator
A mass flow rate reading (from a mass flow meter or a combustion calculation) does not directly tell you how fast gas is actually moving through a duct - that requires knowing the gas density and cross-sectional area too.
Formula: v = ṁ / (ρ × A)
Example: 0.5 kg/s of gas at 1.2 kg/m³ density through a 100 cm² cross-section moves at about 41.7 m/s.
How to Use This Calculator
- Enter mass flow rate.
- Enter gas density at the actual operating temperature and pressure.
- Enter the duct or pipe's cross-sectional area.
This is a straightforward rearrangement of the mass flow continuity equation, useful whenever a known mass flow needs to be checked against a duct's velocity design limits.