Hydraulic Horsepower Calculator

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

1. Enter flow rate in gallons per minute (GPM).
2. Enter pressure in PSI.
3. 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.

Flow and Pressure: The Two Halves of Hydraulic Power

Hydraulic power is the product of flow (how fast fluid moves, in GPM) and pressure (the force behind it, in PSI). High pressure with low flow suits slow, forceful tasks like a press; high flow with lower pressure suits fast actuators. The 1714 constant converts these into horsepower. Because both terms multiply, doubling either one doubles the power — which is why system designers balance pump displacement against relief-valve pressure.

Efficiency and Input Power

The formula gives ideal hydraulic horsepower delivered to the fluid. Real pumps lose energy to internal leakage and friction, so the electric motor or engine driving the pump must supply more — divide by pump efficiency (typically 0.80–0.90) to get the true input horsepower. Always size the prime mover on that larger input figure, with margin for pressure spikes.

Hydraulic HP by Flow and Pressure

Flow (GPM)	Pressure (PSI)	Hydraulic HP
5	1,500	4.4
10	2,000	11.7
20	3,000	35.0
40	2,500	58.3