Use this engineering calculation for a transparent preliminary estimate or independent arithmetic check when geometry, materials, loads, operating conditions, and units are defined consistently.

Absolute Pressure Pascals (Pa)

Required number input.

Vapor Pressure Pascals (Pa)

Required number input.

Density Kg Per M3 (kg/m³)

Required number input.

Speed Meters Per Second (m/s)

Required number input.

Cavitation number (p−pv)/(½ρv²) using local absolute pressure and vapor pressure. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Cavitation Number

The resulting cavitation number returned as a number.

• Hydraulic equations require consistent datum, fluid properties, geometry, roughness, flow regime, and loss coefficients. Cavitation, air entrainment, unsteady flow, fittings, sediment, free-surface effects, and pump behavior may require a network or numerical model.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check assumptions against drawings, measurements, current material data, and the applicable design code. Apply required load combinations and safety factors, then obtain qualified review and testing for consequential designs.

• Pump NPSH Available

  Available pump NPSH from absolute suction pressure head plus velocity head minus vapor pressure head; supply losses are already reflected in suction pressure.

• Darcy Weisbach Pressure Drop

  Darcy–Weisbach pressure drop in a straight constant-diameter pipe from a supplied Darcy friction factor; excludes local losses.

• Mach Number Compressible

  Mach number as flow speed divided by local speed of sound; no constant-speed-of-sound approximation.