Pump Sizing

Required head and flow.

Run the calculator

Example

You enter

Flow (gpm) 100
Total dynamic head (ft) 80
Pump efficiency (0-1) 0.65
Fluid specific gravity 1

You get

Hydraulic hp 2.02
Shaft hp 3.108

Details, formula, and sources

Hydraulic HP = (GPM × TDH × specific_gravity) / 3960; shaft (brake) HP = hydraulic HP / pump_efficiency. Total dynamic head (TDH) is supplied by the user.

Hydraulic Institute by name; Hazen-Williams (AWWA M11 5th ed.) for friction term.

Hydraulic Institute standards licensed; principles free in published engineering texts and university OCW.

Estimate. AHJ and licensed plumber / gas fitter govern. Verify against the IPC / IFGC edition adopted in your jurisdiction.

Field names used by the API: flow_gpm, total_dynamic_head_ft, efficiency, fluid_specific_gravity, hydraulic_hp, shaft_hp

Pump efficiency 65% unless user supplies a curve pointHydraulic Institute typical for end-suction centrifugal
Water density / specific gravity 1.000 unless user supplies60 °F freshwater