Pump Power Calculator

About this calculator

This calculator finds the hydraulic power a pump delivers using P = ρ·g·Q·H, where ρ is fluid density, g is gravitational acceleration, Q is the volumetric flow rate, and H is the total head (the height plus friction losses the pump must overcome) — then divides by pump efficiency to get the actual shaft power the motor must supply, since real pumps always lose some energy to friction and turbulence.

Mechanical and civil engineers use this to size pumps for water supply, irrigation, HVAC and industrial fluid-handling systems, and to estimate motor power requirements and energy costs. Enter the flow rate, total head, fluid density and pump efficiency to get hydraulic and shaft power.