Performance Coefficient Calculator

What Is Pump Performance Coefficient?

The performance coefficient (or hydraulic efficiency) of a pump or turbine compares useful fluid power to shaft power input. A value near 100% means most electrical or mechanical energy becomes head on the fluid. Values below 70% often signal wear, cavitation, or an oversized impeller.

Performance Coefficient Formula

Hydraulic power delivered to the fluid is:

$$P_h = \rho \times g \times Q \times H$$

The performance coefficient is:

$$\eta = \frac{P_h}{P} = \frac{\rho \times g \times Q \times H}{P}$$

where:

$\rho$ — fluid density (kg/m³)
$g$ — gravitational acceleration (m/s²)
$Q$ — volumetric flow rate (m³/s)
$H$ — total head (m)
$P$ — shaft power (W)

Related tools: Hazen Williams Calculator and Pipe Weight Calculator.

Frequently Asked Questions

What is a good pump efficiency?

Centrifugal water pumps often run between 65% and 85%. High-efficiency designs can exceed 90% at their best efficiency point.

How do I convert GPM to m³/s?

Multiply GPM by 0.00006309. One gallon per minute equals about 6.31 × 10⁻⁵ cubic meters per second.

Does fluid density matter?

Yes. Hydraulic power scales with density. Water at 1000 kg/m³ is the usual baseline, but oil or slurry needs the actual density value.

Can efficiency exceed 100%?

No. Values above 100% indicate a measurement error, wrong units, or incorrect head or flow readings.

Is this the same as COP?

No. Coefficient of performance applies to heat pumps and refrigerators. This tool uses the fluid mechanics definition for pumps and turbines.

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What Is Pump Performance Coefficient?

Performance Coefficient Formula

Frequently Asked Questions

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