Pump Specific Speed Calculator

Calculate pump specific speed from rotational speed, flow rate and head.

Calculator

Specific speed (Ns) —

Formula

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

Ns = N · √Q / H3/4

Where:

  • Ns = pump specific speed
  • N = rotational speed [rpm]
  • Q = flow rate [m³/h]
  • H = head [m]

Engineering note

Specific speed depends on the unit convention. This calculator uses the common metric pump convention with Q in m³/h and H in m. Always verify which convention is required by your project, company standard or customer specification.