Pump Specific Speed Calculator
Dimensionless N_s identifies the impeller type your duty wants — radial, mixed or axial.
N_s is calculated once at BEP and defines the hydraulic family. Very low N_s duties (< 10) often suit multistage or PD pumps better.
Formula
Pump Specific Speed Calculator is a free specific speed for pump engineers, plumbers and plant designers — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Pump Specific Speed Calculator
Dimensionless N_s identifies the impeller type your duty wants — radial, mixed or axial. The calculation implements N_s = N·√Q / H^0.75 (rpm, m³/s, m) (Stepanoff, Centrifugal and Axial Flow Pumps). N_s is calculated once at BEP and defines the hydraulic family. Very low N_s duties (< 10) often suit multistage or PD pumps better.
How to use Pump Specific Speed Calculator
- 1Enter Speed in rpm.
- 2Enter Flow at BEP in m³/h.
- 3Enter Head per stage at BEP in m.
- 4Read Specific speed (metric) instantly — no submit button needed.
- 5Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Pump Specific Speed Calculator?
- ✓Implements the standard formula — N_s = N·√Q / H^0.75 (rpm, m³/s, m)
- ✓Reference cited on-page: Stepanoff, Centrifugal and Axial Flow Pumps
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Built-in engineering verdict flags out-of-range results instantly
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Pump Specific Speed Calculator use?+
It computes N_s = N·√Q / H^0.75 (rpm, m³/s, m), per Stepanoff, Centrifugal and Axial Flow Pumps. The formula is displayed under the result along with a worked example substituted with your own inputs.
What should I keep in mind when using this calculator?+
N_s is calculated once at BEP and defines the hydraulic family. Very low N_s duties (< 10) often suit multistage or PD pumps better.
Can I use this for pump selection?+
Use it to establish the duty (flow, head, NPSH, power) and then pick a pump whose curve passes through that point near best efficiency. The tool gives you the engineering numbers a supplier will ask for.
Is the Pump Specific Speed Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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