GPM Calculator
Estimate flow rate in gallons per minute based on pipe diameter, pressure, and length.
Pipe Diameter (inches)
Please enter a positive diameter.
Pressure (PSI)
Please enter a positive pressure.
Pipe Length (feet)
Please enter a positive length.
Roughness Coefficient (C factor)
PVC / Smooth Pipe (140)
Copper / Brass (130)
Steel (120)
Galvanized (100)
Cast Iron (80)
Calculate GPM
Estimated Flow Rate
0.00 GPM