Suction Specific Speed Calculator

Calculate suction specific speed from rotational speed, flow rate and NPSHa.

Calculator

Suction specific speed (Nss) —

Formula

The metric suction specific speed is calculated using Q in m³/h:

Nss = N · √Q / NPSHa3/4

Where:

  • Nss = suction specific speed
  • N = rotational speed [rpm]
  • Q = flow rate [m³/h]
  • NPSHa = available NPSH [m]

Engineering note

Suction specific speed is sensitive to the unit convention and the flow basis used. This calculator uses the common metric pump convention with Q in m³/h and NPSHa in m. Verify the required method against the applicable standard or customer specification.