Pump Horsepower Calculator
The Pump Horsepower Calculator determines required pump power from flow rate, total dynamic head, and pump efficiency. Essential for pump selection and motor sizing.
Educational estimate. Calculator results are for planning and information only, not financial, tax, medical, legal, or engineering advice. Verify important decisions with official sources or a qualified professional.
Pump Horsepower Calculator
Pump Power & HP from Flow Rate & Head
📐 Formula & Method
Hydraulic Power
Q is flow in m3/s after converting from L/min; rho is fluid density; g = 9.81 m/s2; H is total dynamic head.
Shaft Power and HP
Efficiency is entered as percent and converted to decimal. 1 mechanical horsepower = 745.7 W.
📋 How to Use
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1
Enter flow in L/min.
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2
Enter total dynamic head, pump efficiency, and density.
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3
The calculator converts flow to m3/s, computes hydraulic power, then shaft kW and HP.
🧮 Worked Examples
Validation case
500 L/min, 20 m head, 75% efficiency, water density 1000 kg/m3.
Pump Horsepower Calculator — Engineering Reference
Pump horsepower is based on hydraulic work required to lift or pressurise a flow of fluid.
Use a motor service factor and the manufacturer pump curve for final motor selection.
🔬 Methodology & Accuracy
Formula: Converts L/min to m3/s, calculates hydraulic power, divides by pump efficiency, and converts shaft watts to kW and HP.
Data sources: Standard hydraulic power equation and mechanical horsepower conversion.
Last reviewed: June 2026 · General formula used: Hydraulic Power · Accuracy: Results are precise to two decimal places using IEEE-754 double-precision arithmetic. Intended for educational and planning use only.
For informational purposes only. Results are estimates based on the inputs and formulas provided. For financial, tax, medical, or legal decisions, consult a qualified professional. Rates and regulations change — always verify current figures with official sources.