About The NPSH Available Calculator

The NPSH Available Calculator estimates pump suction NPSHa from atmospheric pressure, vapor pressure, fluid density, static head, and suction line loss. It is a quick helper for pump cavitation screening.

How to Use the NPSH Available Calculator Online

1. Enter the required inputs in the fields above using the units shown on the labels.
2. Select any mode, shape, or method options so the calculation matches your scenario.
3. Run the calculation and review the result summary in the output panel.
4. Check the units, assumptions, and project requirements before using the result outside preliminary review.

Choosing Options Correctly

Pressures are entered in kPa, density in kg/m^3, and heads/losses in meters. Static head can be positive for flooded suction or negative for suction lift.

Common Use Cases

• Estimate available suction head for a pump installation.
• Compare NPSHa against a pump curve NPSHr value.
• Check how suction losses or static lift affect cavitation margin.

Quick FAQ

What is NPSH available?
It is the suction head available at the pump above the liquid vapor pressure head.

Does it choose a pump?
No. Compare NPSH available against the pump curve NPSH required with an appropriate margin.

Why does vapor pressure matter?
Higher liquid temperature increases vapor pressure and reduces NPSH available, raising cavitation risk.

What losses should be included?
Include suction pipe friction, fittings, strainers, valves, and static suction lift or head.