Pump Power Calculator

Estimate hydraulic and input power for a pump.

Steady incompressible liquid series systems with user pump curves. This standalone quick calculator remains available below.

Live concept view — geometry scales with the entered design condition.

PRELIMINARY RESULT

Hydraulic power4.41 kW

Estimated pump shaft power: 6.31 kW

Calculation detail

Formula: P = ρgQH / η

Hydraulic power is based on water density; shaft power accounts for pump efficiency; motor electrical input requires motor efficiency and other drive losses.

Pump Power Calculator: operating questions

Does calculated input power select the motor?

Not alone. Motor efficiency, service factor, operating range, fluid density, start conditions and the maximum absorbed power on the pump curve must be reviewed.

Is total head the discharge pressure reading?

No. Total dynamic head is an energy-per-weight difference including pressure, elevation and velocity terms plus system losses, evaluated between defined points.

Why is NPSH absent from the power result?

NPSH is a suction-side cavitation check rather than a term in the basic hydraulic-power identity. It remains mandatory for pump selection where applicable.

Illustrative input values and units
Parameter	Unit	Example
Flow rate	L/s	15
Total head	m	30
Pump efficiency	%	70

Technical verification

Equation checked: 2026-09-15 · Units checked: 2026-09-15 · Independent numerical case: Pass

Source basis: MANUFACTURER DATA — Grundfos, Induced power and pump power boundaries

Unit basis: L/s ÷1000 → m³/s; W ÷1000 → kW; % ÷100

Independent example: 15 L/s, 30 m, water 1000 kg/m³, g=9.81 m/s², 70%: 4.4145 kW hydraulic; 6.30643 kW shaft.

Scope: Density and gravity are design assumptions. Motor losses, NPSH, pump/system curves and operating-point selection are separate.

Technical verification is not professional engineering certification and does not approve a specific real-world design.