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Pump Specific Speed (Ns)

The dimensionless-style speed that classifies the impeller geometry — radial, mixed or axial — for a given duty.

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m³/h
m
rpm

Result

Fill in the fields — the result appears as you type.

Method & assumptions
Ns = N · √(QUSgpm ÷ i) ÷ Hft0.75

US-convention specific speed (Q in US gpm, H in ft). Head is per stage — divide total head by the number of stages before entering it. Double-entry impellers take half the flow.

Engineering aid only — verify results against the applicable code edition and the equipment datasheet before committing to a design.

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