NPSH available for four cases side by side — tank or suction-gauge route, altitude, hot liquid, low level — against the vendor NPSH3 curve with margins, suction specific speed and vortex submergence.
USD 29 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
Four cases at once
Rated, maximum flow, hot liquid and low level — or any four of your own.
Two routes
From the suction vessel (open tank at altitude, closed vessel, boiling liquid) or from a suction gauge reading.
Vendor NPSH3 curve
Fitted and scaled to your speed; recommended margins by service from the Pump Handbook; ANSI/HI 9.6.1 named as the authority.
Liquids done properly
Vapour pressure from the built-in liquid list, bubble point for mixtures, or your own values; flashing and boiling checks.
Extra checks
Suction specific speed, suction velocity and vortex submergence.
Print-ready report
Case table, findings and the NPSHa / NPSHR chart.
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 hot-water pump taking 120 m³/h from an open tank, checked for four cases side by side — rated (80 °C, 3 m level), maximum flow (150 m³/h), hot (95 °C) and low level (1 m) — against the vendor's NPSH3 curve. The workbook gives: NPSHa 8.18, 7.91, 4.30 and 6.18 m against NPSHR 4.47–5.85 m. Three cases pass; at 95 °C the pump cavitates (ratio 0.96), and the report lists the fixes. It also flags the suction velocity above 1.5 m/s and a suction specific speed of 8,808, and charts NPSHa and NPSHR against flow.
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 | Reproduces the free web NPSH calculator (7.80 m) and an independent Python model; suction-gauge route checked by hand (8.76 m). |
| Free version | Try the online calculator |
Free calculator, online tool or Excel tool?
| Free calculator | Online tool | Excel tool | |
|---|---|---|---|
| What it does | NPSH available and margin, with water vapour pressure from steam tables and suction-line friction. | The full Excel tool, run in your browser | NPSH available for four cases side by side — tank or suction-gauge route, altitude, hot liquid, low level — against the vendor NPSH3 curve with margins, suction specific speed and vortex submergence. |
| Cost | Free, no sign-up | 3 runs for USD 9, or every online tool for USD 15 a month | USD 29 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. |