Hydraulic Horsepower Calculator
Calculate hydraulic horsepower from flow rate (GPM) and pressure (PSI) instantly.
Hydraulic horsepower measures the power a hydraulic system delivers through fluid flow and pressure. It's the key figure for sizing pumps, motors, and power units in fluid-power and industrial systems.
Hydraulic Horsepower Formula
The constant 1714 converts gallons-per-minute and pounds-per-square-inch into horsepower. Real systems aren't perfectly efficient, so the motor driving the pump must supply more than the theoretical hydraulic horsepower — typically 80–90% efficiency for a good pump.
How to Use This Calculator
- Enter flow rate in gallons per minute (GPM).
- Enter pressure in PSI.
- Set efficiency (default 85%) to see the input horsepower the motor needs.
Worked Example
To convert the result to kilowatts use the HP to kW calculator, or for pump sizing from head instead of pressure see the pump horsepower calculator.
Frequently Asked Questions
Hydraulic horsepower = (Flow in GPM × Pressure in PSI) ÷ 1714. This gives the theoretical power delivered to the fluid.
It's the unit-conversion factor that turns gallons per minute and pounds per square inch into horsepower. It comes from combining the definitions of those units.
Hydraulic HP is the useful power in the fluid; input HP is what the motor must supply, found by dividing hydraulic HP by the pump's efficiency.
Most hydraulic pumps run 80–90% efficient. Use 85% as a reasonable default if you don't have the manufacturer's figure.
Multiply hydraulic horsepower by 0.7457 to get kilowatts, or use our HP to kW calculator for an instant conversion.