HVAC Duct Friction & CFM Calculator
Precision engineering tool for duct sizing and friction loss analysis.
Calculate Size
Calculate Friction
Units
Imperial (CFM / In)
CFM
Friction Rate (in.wg/100ft)
Duct Shape
Round
Rectangular (Fixed 2:1)
Recommended Diameter
--
inches
View Standard Sizes
Common Duct Sizes
Diameter (in)
CFM @ 0.1 Frict
6"
100
8"
200
10"
350
12"
600
14"
900
16"
1300