Duct Velocity & Noise Calculator

Calculate duct velocity, velocity pressure, and estimated noise criteria rating

Volume of air flowing through the duct section in cubic feet per minute.
CFM
For round ducts, enter diameter. For rectangular, enter width. For oval, enter major axis.
inches
For rectangular ducts, enter height. For oval ducts, enter minor axis. Leave default for round ducts.
inches
Select the cross-sectional shape of the duct. Equivalent round diameter is calculated for rectangular and oval ducts.

Results

VelocityFPM
Velocity Pressurein.wg
Estimated Noise CriteriaNC
Recommended Max VelocityFPM
Equivalent Round Diameterinches
References: ASHRAE Fundamentals Handbook, SMACNA Duct Design. Velocity Pressure = (V/4005)². NC rating estimated from duct velocity: offices NC 25-35, retail NC 35-45.