Duct Calculator

Calculate flexible and sheet metal duct friction loss, equivalent rectangular duct and more.

Flexible Duct Friction Loss Calculator

Enter Friction Loss Per 100' of duct (inches of water), Duct Airflow (CFM), Duct Length and the number of bends.
Read Duct Diameter (inches) and Duct Velocity (FPM).

Friction Loss
(inches water)

Duct Airflow
(CFM)

Duct Length
(feet)

90 Bends
(quantity)

45 Bends
(quantity)

180 Bends
(quantity)

Duct Diameter (inches)11.9

Duct Velocityr(FPM)2591