Abstract: An earthworking machine having a working tool at the end of an articulated arm is automatically calibrated. The calibration method includes collecting angular position data relating to different articulated components, after a series of movements of the end of the working tool between reference points located in accordance with a given geometrical configuration. These data are derived by imprecisely positioned detectors on each articulated component and then sent to a machine calibration system that executes a calculation module of the calibration system to determine, by use of known input data, unknown parameters which, once determined, control a luminous indicator display which guides the machine operator in the horizontal and/or vertical movements for the depth of the tool.