Pump Shaft Power Calculator
Calculate pump shaft power with transparent engineering inputs and the displayed formula.
Run deterministic checks for missing or mixed units, physical bounds, detectable out-of-range values and formula applicability. This is not an engineering approval or a complete code/compliance check.
Export the current calculation inputs and outputs with formula, assumptions, confirmed source credits, automated verification status, tool version and timestamp.
PROFENG Pro unlocks calculation-record exports. The calculation itself remains free.
PROFENG provides this tool for engineering screening and educational use. Check the calculation basis, units, physical assumptions, applicable standards, safety factors, equipment data and project-specific requirements before design, procurement or operation.
Turn this result into a calculation record
Carry the tool context into the PROFENG calculation-check and record workspace without implying certification or engineering approval.
Why use this pump shaft power calculator?
Calculate pump shaft power with transparent engineering inputs and the displayed formula. The displayed relationship is Pshaft = ρgQH / η.
What this calculation does
This calculator determines shaft power from fluid density, flow, head, pump efficiency. Use it for preliminary hydraulic screening, sanity checks and transparent comparison of operating cases before detailed equipment or piping design.
Formula and engineering variables
Pshaft = ρgQH / η
| Variable | Definition | Unit | Working guidance |
|---|---|---|---|
rho | Fluid density | kg/m³ | Illustrative screening band: 0 to about 9,980 kg/m³. This is not a design limit. |
flow | Flow | m³/s | Illustrative screening band: 0 to about 1 m³/s. This is not a design limit. |
head | Head | m | Illustrative screening band: 0 to about 300 m. This is not a design limit. |
eta | Pump efficiency | % | Physical screening range: greater than 0% and no more than 100%. |
Ranges above are screening guidance or physical bounds where stated. They are not code limits or manufacturer ratings.
Calculated outputs
- Shaft power (kW): rho*9.80665*flow*head/(eta/100)/1000
Worked example
- Fluid density (rho) = 998 kg/m³
- Flow (flow) = 0.05 m³/s
- Head (head) = 30 m
- Pump efficiency (eta) = 75 %
(998)*9.80665*(0.05)*(30)/((75)/100)/1000 = 19.574 kWShaft power: 19.574 kWAssumptions
- Inputs describe one consistent operating case and use the displayed units.
- Fluid properties are represented by the entered values and are treated as uniform for the calculation.
- Steady-state behavior is assumed unless the formula explicitly includes time dependence.
Limitations
- Transient effects, fittings, compressibility, cavitation margin and manufacturer performance data may require separate treatment.
- Final piping and rotating-equipment design must use the governing project criteria and applicable codes or standards.
- Density is treated as constant over the calculation.
- Flow rate and total developed head refer to the same operating point.
- Efficiency is expressed as a fraction greater than zero and no more than one.
- The relationship converts hydraulic power to required shaft power; motor and drive losses are separate unless included in the entered efficiency.
- The displayed default values are a worked example only; replace them with traceable project or measurement data.
Formula source and acknowledgement
Relationship used: Pshaft = ρ g Q H / η for a pump delivering hydraulic head H at volumetric flow Q with overall pump efficiency η.
The relationship used here follows Igor J. Karassik, Joseph P. Messina, Paul Cooper, Charles C. Heald, Pump Handbook 4th edition (2008), McGraw Hill.
Credit for the underlying method belongs to the cited author(s). PROFENG presents its own implementation and wording and is not affiliated with or endorsed by the authors or publishers.
Limits of use for this relationship
- Density is treated as constant over the calculation.
- Flow rate and total developed head refer to the same operating point.
- Efficiency is expressed as a fraction greater than zero and no more than one.
- The relationship converts hydraulic power to required shaft power; motor and drive losses are separate unless included in the entered efficiency.
Read the PROFENG methodology for formula sourcing and automated checks →
How to use it
Start with the inputs shown above, review the assumptions or options, then generate the result. Where the tool creates a file, keep the original until you have opened and checked the downloaded output.
Frequently asked questions
What does Pump Shaft Power Calculator calculate?
This calculator determines shaft power from fluid density, flow, head, pump efficiency. Use it for preliminary hydraulic screening, sanity checks and transparent comparison of operating cases before detailed equipment or piping design.
What formula does Pump Shaft Power Calculator use?
The calculator uses Pshaft = ρgQH / η. Every input used by the implementation is listed in the variable table on this page.
How is the worked example for Pump Shaft Power Calculator checked?
PROFENG substitutes the displayed default values into the implemented relationship and compares the result against automated verification cases where an independent verifier is available.
What assumptions matter most for Pump Shaft Power Calculator?
Inputs describe one consistent operating case and use the displayed units. Fluid properties are represented by the entered values and are treated as uniform for the calculation. Steady-state behavior is assumed unless the formula explicitly includes time dependence.
Can I use this result for final design or procurement?
Use it as an engineering screening calculation. Final design, procurement, operation or compliance decisions require project-specific data and the applicable engineering method, standard or manufacturer information.
QA, changelog and corrections
Last QA update: 30 September 2026.
Automated verification passed – 30 September 2026 – six numerical cases checked, with dimensional checks, independent cross-checks for calculators, and unit round-trip checks for converters where applicable.
Changelog
30 September 2026 – source/indexation status, metadata and correction pathway reviewed. Engineering tools display the automated verification label only when they are inside the passing Part 3 verification scope.