Friction Loss Calculator

Calculate pressure drop (friction loss) in pipes using the Hazen-Williams equation.

GPM
inches
feet
C
PVC=150, Steel=130, Cast Iron=100
Friction Loss
—PSI total loss
PSI per 100 ft—
Velocity—

Hazen-Williams Formula

f = 0.2083 × (100/C)^1.852 × Q^1.852 / d^4.8655. Where f = friction loss (ft/100ft), C = roughness coefficient, Q = flow (GPM), d = diameter (inches).