Head, efficiency and power curves for any impeller diameter and speed from the vendor's curves, the motor size with API 610 margins, low-flow alerts and a field test against the curve.
USD 39 one-time purchase
Download the sample report (PDF)
Buying several tools? Get the Pumps Complete Kit — USD 129
Need it once? Use it online: check your data free, unlock results from USD 9 for 3 runs.
What it does
Curves for any impeller
Head, efficiency and power curves for any diameter and speed, blended from up to four vendor curves; the existing curves and the new one drawn together, with drop lines to the duty point.
Motor sizing
Shaft power at duty and at the end of the curve; motor rating with API 610 margins or non-overloading, rounded to standard IEC sizes.
Design checks
Head margin, trim diameter or VFD speed that meets the duty, throttling loss and its yearly cost.
Low-flow alerts
Minimum stable and thermal flow screening, % of BEP, temperature rise — with plain-language warnings for oversized pumps.
Field test
Total head, efficiency and wire-to-water efficiency from gauges and motor power, corrected to curve speed, with the efficiency gap in kW and money.
54 pumped liquids
Built-in pump liquid list with vapour-pressure checks, mixtures of up to 8 liquids, or your own properties.
Built for engineers
- Visible formulas — nothing hidden, so you can check every step.
- Fully referenced — methods from the standard references, checked against their published worked examples.
- Safe to share — sheets are protected against accidental edits, with an open password so you can still customise.
- Built-in input checks — clear warnings for impossible inputs and values outside typical ranges.
For engineering estimates; verify against site data. Code-based methods are aligned with the publicly documented procedure; they are not a licensed reproduction or a certification.
Preview the workbook
Real pages from the workbook with its built-in example loaded (example data, not a measured plant). Choose a page below, or select the large image to enlarge it.
A worked case
The case: a cooling-water pump with a 560 mm impeller at 740 rpm, rated for 6,000 m³/h at 26 m, on a 630 kW motor, with the vendor’s curve. The workbook gives: 29.1 m and 85.8 % efficiency at the duty (92.5 % of the BEP flow), shaft power 552 kW and 88 % motor load. The findings flag 12 % excess head — trimming to about 535 mm (or 707 rpm) saves about 60 kW, USD 48,253 a year — and that the 2,200 m³/h minimum case is below the pump's minimum flow, so a bypass of at least 394 m³/h or a VFD is needed. Head and efficiency curves are charted at the selected impeller and speed.
Specification and checks
| Format | Excel workbook (.xlsx), no macros |
| Version | v1.0 |
| Works in | Excel 2010 or later, Windows and Mac |
| Units | SI, US and British, mixed freely |
| Includes | Guide tab with method and references, calculator, print-ready report |
| Checked against | An independent Python model gives the same head, efficiency, power, trim and VFD results for interpolated and extrapolated impellers (4+ significant figures); field test reproduces the free web calculator. |
| Free version | Try the online calculator |
Free calculator, online tool or Excel tool?
| Free calculator | Online tool | Excel tool | |
|---|---|---|---|
| What it does | Total head, hydraulic and shaft power, efficiency from field readings — and what a worn pump costs a year. | The full Excel tool, run in your browser | Head, efficiency and power curves for any impeller diameter and speed from the vendor's curves, the motor size with API 610 margins, low-flow alerts and a field test against the curve. |
| Cost | Free, no sign-up | 3 runs for USD 9, or every online tool for USD 15 a month | USD 39 once, yours to keep |
| Input checks and findings | Basic warnings | Every input checked, with findings and recommendations | Every input checked, with findings and recommendations |
| Report for your calculation file | Print the web page | Printable results sheet | Print-ready report with your plant, tag, document number, revision and sign-off |
| Formulas | Method described on the page | Method described in the guide | Every formula visible in its cell |
| Save, edit and rerun your cases | — | Each run separately | Yes — keep and edit your own file |
| Works offline, on a plant PC | — | — | Yes — Excel 2010 or later, Windows and Mac |
Compatibility, licence and support
| File | Excel workbook (.xlsx), no macros, version v1.0; works in Excel 2010 or later on Windows and Mac. Sheets are protected against accidental edits, with an open password so you can customise. |
| Licence | Single user. A team licence (up to 5 named users) is 3 × the shop price; site licences on request — licence terms. |
| Updates | Updates to this major version are included; download them again from the link in your receipt. |
| Support | Email [email protected] with your order number — questions on the method, your inputs or your results are welcome. |
| Refunds | If the tool does not work as described, or has an error we cannot fix, email [email protected] with your order number within 14 days of purchase and we will refund you in full. Refunds are not offered for a change of mind once a file has been downloaded. Read the full refund policy. |