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Centrifugal Pump Specific Speed Nq Calculator

Nq = n√Q / H^(3/4) — pump type classification number.

Calculates the specific speed (Nq) of a centrifugal pump to identify pump type (radial, mixed, axial) from speed, flow, and head.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

Nq = n × √Q / H^(3/4); n in rpm, Q in m³/s, H in m

In depth

Calculates the specific speed (Nq) of a centrifugal pump to identify pump type (radial, mixed, axial) from speed, flow, and head.