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Pump Head & Power Calculator — TDH, Shaft HP & Electrical kW
Calculate pump shaft power and estimated electrical input from flow and total dynamic head, or build head from net lift, friction and pressure.
ELECTRICAL TOPICPump Head & Power Calculator
Your result
PUMP DUTY POINTREADY
—Enter values below and press Calculate.
RESULT DISPLAYFlow + head → HP
Calculation details & exports
Inputs used
ElectricalTopic.com Tools© 2026 ElectricalTopic.comFlow + head → HPFormula and worked example
TDH = net static lift + friction head + pressure_Pa / (ρg). Hydraulic kW = ρ × g × Q_m³/s × H / 1000. Shaft kW = hydraulic kW / pump efficiency. Electrical kW = shaft kW / motor efficiency. Mechanical HP = shaft kW / 0.7456998716; g = 9.81 m/s².
Worked example
For water at 1000 kg/m³, 10 m³/hour and 30 m TDH, with 70% pump efficiency and 90% motor efficiency: hydraulic power = 0.8175 kW; shaft power = 1.1679 kW / 1.5661 HP; estimated electrical input = 1.2976 kW.
Using this tool
Enter the actual equipment and project values. The Use example button loads an illustrative case. Calculation happens in your browser; no Python, API key or account is required. Use the result details to see the inputs and scope, copy the result, download CSV or print.
TDH में actual net lift, friction और आवश्यक pressure शामिल होते हैं। Closed-loop system में building height को सीधे pump head न मानें। Pump efficiency और motor efficiency अलग inputs हैं।
Common questions
Is TDH the same as building height?
Not generally. Closed-loop static elevation largely cancels. An open system may require net static lift plus friction and the required terminal pressure difference.
Does calculated HP select a motor or pump?
It is the shaft-power requirement at the entered duty point. Check the actual pump curve, operating range/BEP, motor allowance and starting requirements.
What else affects pump selection?
NPSH/cavitation, viscosity, liquid temperature, pipe-system losses and the manufacturer performance curve are outside this arithmetic power model.
Related practical guides
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Formula references and model scope
Formula review: 2 November 2026. Examples are illustrative. Enter project-specific data; a planning result does not certify an installation or equipment selection.
