PipeSage
Fluid Mechanics / Pump Sizing

Pump Power Calculator

Enter flow rate, total dynamic head, and pump efficiency to get both hydraulic power and the shaft (motor) power you need to spec.

Shaft Power
kW
Hydraulic Power
kW

How this is calculated

P_hydraulic = ρ·g·Q·H   |   P_shaft = P_hydraulic / η
Enter values above to see the worked calculation.

When to use this calculator

Hydraulic power is the theoretical minimum energy needed to move the fluid; shaft power is what the motor actually has to deliver once pump inefficiency is accounted for. Always size the motor to shaft power, with margin, not hydraulic power.

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