How to use the Hydraulic Pump Horsepower Calculator
- Enter the volume moved over the stated time. Pressure difference is outlet pressure minus inlet pressure for the incompressible-fluid model.
- Enter delivered fluid volume, elapsed time and its unit, pressure difference and overall pump efficiency.
- Select Calculate. Review the result and its working; if you change an input, calculate again before copying or sharing.
Hydraulic Pump Horsepower formula
Delivered volume divided by elapsed time gives flow. Pressure difference times flow gives hydraulic power; dividing by efficiency gives required shaft power.
Shaft hp = [ΔP(psi) × 144 × V(ft³) ÷ time(seconds)] ÷ (550 × efficiency)
What the terms mean
- Delivered fluid volume
- Entered in ft³.
- Time taken
- Elapsed duration for the delivered volume, expressed in the selected time unit.
- Pressure difference
- Entered in psi.
- Overall pump efficiency
- Hydraulic output power divided by shaft input power, entered as a percentage.
Hydraulic Pump Horsepower worked examples
Estimate shaft power at eighty-percent efficiency
A hydraulic pump delivers 1 ft³ in 1 minute across a pressure difference of 100 psi. Overall pump efficiency is 80%.
- Flow = delivered volume ÷ elapsed seconds
- Hydraulic hp = pressure difference (psi) × 144 × flow (ft³/s) ÷ 550
- Shaft hp = hydraulic hp ÷ efficiency
Answer: 0.545455 mechanical hp. Hydraulic output power: 0.436364 hp; Flow rate: 1 ft³/min; Required shaft power: 0.406745 kW.
Compare an ideal-efficiency hydraulic calculation
A pump delivers 2 ft³ in 1 minute across 100 psi. Use an idealized 100% efficiency to compare shaft power with hydraulic output power.
- Flow = delivered volume ÷ elapsed seconds
- Hydraulic hp = pressure difference (psi) × 144 × flow (ft³/s) ÷ 550
- Shaft hp = hydraulic hp ÷ efficiency
Answer: 0.872727 mechanical hp. Hydraulic output power: 0.872727 hp; Flow rate: 2 ft³/min; Required shaft power: 0.650793 kW.
Hydraulic Pump Horsepower Calculator FAQs
Why is elapsed time required?
Power is work per time. The delivered volume divided by time gives flow, which combines with pressure difference to determine hydraulic power.
Can this size a gas compressor?
No. Compressible-gas power depends on thermodynamics. This page uses a steady incompressible-fluid hydraulic model.
Measurement guide for Cubic Feet to Horsepower
Measure the volume delivered over a known time. Pressure difference is outlet minus inlet pressure; overall efficiency must describe the pump and drive system.
Assumptions and limits
Volume does not directly specify horsepower. The calculation estimates steady hydraulic power; gas compression, elevation changes not represented by pressure, and transient loads need further modelling.
Steady incompressible-fluid hydraulic power estimate. Gas compression needs a thermodynamic model. Volume alone does not specify horsepower.
Check your result
Review flow rate and hydraulic output power first. At less than 100% efficiency, the required shaft power is greater than the hydraulic output power.