A lifting device (10) comprises a support element (14), a lifting arm (18) which is pivotably connected to the support element, an actuator (46) which is pivotably connected to the lifting arm (18) and the support element (14) for raising and lowering the lifting arm (18), and a load cell (82) for outputting a load signal corresponding to a load imparted to the actuator (46). Also provided is a first torque sensor (78) for outputting a first torque signal corresponding to a first torque imparted at at least one of the pivot (44) between the lifting arm (18) and the support element (14) and along the lifting arm (18), a second torque sensor (80) for outputting a second torque signal corresponding to a second torque imparted at at least one of the pivot (80) between the actuator (46) and the support element (14), the pivot (48) between the actuator (46) and the lifting arm (18) and along the actuator (46), and a displacement sensor (84) for outputting a displacement signal corresponding to a displacement of the actuator (46). Calculation means (86) is also provided for calculating a weight at a distal end (50) of the lifting arm (18) based on the load signal, first and second torque signals, and the displacement signal.
