Online Pump Specific Speed Calculator at Best Efficiency point .

## Pump Specific Speed at Best Efficiency Point Formulas:

**Imperial Units:**

N_{s }= ( N * (Q)^{1/2 }) / (H)^{3/4}.

where:

Ns = specific speed.

N = pump speed, rpm.

Q = flow, gpm.

H = head, ft.

Values are taken at best efficiency point (BEP). Pump flow is taken at the largest impeller diameter For double suction impellers pump flow is divided by two.

**SI Units:**

N_{s }= ( N * (Q)^{1/2 }) / (H)^{3/4}.

where:

Ns = specific speed.

N = pump speed, rpm.

Q = flow, m3/h.

H = head, m.

Values are taken at best efficiency point (BEP). Pump flow is taken at the largest impeller diameter For double suction impellers pump flow is divided by two.