Horsepower for a Hydraulic Motor
To calculate the horsepower (HP) for a hydraulic motor, you need to know the following parameters:
- Flow Rate (Q): The volume of hydraulic fluid flowing to the motor, typically in gallons per minute (GPM) or liters per minute (LPM).
- Pressure (P): The hydraulic system's pressure, usually in pounds per square inch (psi) or bars.
- Efficiency (η): The efficiency of the motor, usually expressed as a decimal (e.g., 0.85 for 85% efficiency).
Formula for Hydraulic Motor Horsepower
The general formula for calculating the horsepower for a hydraulic motor is:

Where:
- = Pressure (psi)
- = Flow rate (GPM)
- = Efficiency (decimal)
- 1714 is a constant that converts the units to horsepower (for psi and GPM).
Steps to Calculate:
- Identify the Flow Rate ( ) in GPM.
- Identify the Pressure ( ) in psi.
- Estimate the Efficiency ( ) of the hydraulic motor (typically between 0.7 and 0.9).
- Apply the Formula.
Example Calculation:
Let's say you have:
- A flow rate of 50 GPM.
- A pressure of 2000 psi.
- An efficiency of 85% (0.85).
Plugging the values into the formula:

So, the hydraulic motor would require approximately 34.6 horsepower.