Hydraulic Motor Torque Calculator

Inputs

Motor displacement (Vd)

Motor displacement per revolution.

cm³

Pressure drop (Δp)

Pressure drop across the motor, not just pump relief setting.

bar

Motor speed (n)

Target output speed.

rpm

Mechanical efficiency (η_m)

Torque efficiency after friction losses.

Volumetric efficiency (η_v)

Flow efficiency after leakage losses.

Default result

Output torque(T)

114.6N·m

Also computed

Required inlet flow(Q)16.3L/min

Shaft power out3.6kW

Hydraulic power in4.348kW

Input fluid power from Q × Δp.

Method notes 3 notes

Torque comes from pressure drop across the motor, not from nominal pump pressure if valves or lines consume pressure.
Required flow is geometric displacement × speed divided by volumetric efficiency; leakage means the supplied flow must be higher than ideal.
Use the motor manufacturer curve for final sizing; efficiency changes with pressure, speed and oil viscosity.