Pump Power Calculator

Duty point

Fluid flow and the required head or differential pressure.

System resistance input

Head Differential pressure

Fluid flow

Pump head

Fluid

Density, kg/m³

Pump type

Pump efficiency, %

Transmission losses, electrical efficiency and power margin.

Drive type

Drive efficiency, %

Motor efficiency, %

Power margin, %

For 50 m³/h at 30 m head.

Pump shaft power 5.44 kW 5,438 W · 7.29 hp

Hydraulic power4.08 kWtransferred to the fluid

Motor output required5.44 kWincluding drive losses

Electrical input6.04 kWat the stated motor efficiency

Specific energy0.121 kWh/m³per volume pumped

Equivalent head30 mfor the selected fluid

Differential pressure2.94 barρ × g × H

Next standard motor size 7.5 kW Required with a 15% margin: 6.25 kW.

Show detailed calculation

Guide

Flow and head should match the intersection of the pump and system curves, preferably near the recommended operating region around BEP.

Density directly affects power. Higher viscosity also changes head, flow and efficiency and requires manufacturer correction factors.

This power calculation does not check NPSH. Verify separately that NPSH available exceeds NPSH required with an appropriate design margin.

Basic relationship: P_hyd = ρ × g × Q × H. The result applies to incompressible fluids at one steady duty point.