Pump Curve Interpolation Calculator
Fit H = a − b·Q² through three catalogue points and read head at any flow.
A droopless centrifugal curve is close to parabolic — this two-point fit reads intermediate duties within a percent or two of the catalogue.
Formula
Pump Curve Interpolation Calculator is a free pump curve fit 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 Curve Interpolation Calculator
Fit H = a − b·Q² through three catalogue points and read head at any flow. The calculation implements H(Q) = H₀ − b·Q² (b fitted from two known points) (Standard curve-fitting practice for radial pumps). A droopless centrifugal curve is close to parabolic — this two-point fit reads intermediate duties within a percent or two of the catalogue.
How to use Pump Curve Interpolation Calculator
- 1Enter Point 1 flow (shutoff = 0) in m³/h.
- 2Enter Point 1 head in m.
- 3Enter Point 2 flow in m³/h.
- 4Enter Point 2 head in m.
- 5Read Interpolated head instantly — no submit button needed.
- 6Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Pump Curve Interpolation Calculator?
- ✓Implements the standard formula — H(Q) = H₀ − b·Q² (b fitted from two known points)
- ✓Reference cited on-page: Standard curve-fitting practice for radial pumps
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Live worked example: the substitution recomputes from your numbers
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Pump Curve Interpolation Calculator use?+
It computes H(Q) = H₀ − b·Q² (b fitted from two known points), per Standard curve-fitting practice for radial 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?+
A droopless centrifugal curve is close to parabolic — this two-point fit reads intermediate duties within a percent or two of the catalogue.
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 Curve Interpolation 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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