Four basic measurements are performed when calibrating a spherical measurement probe fastened to a tool spindle having a fixed longitudinal position along the spindle axis. Moving the measurement probe transversely towards the calibration sphere yields a basic position of the tool spindle relative to an element with an attached calibration sphere, when measurement probe touches the calibration sphere. The measurement probe is rotated about the spindle axis from one basic measurement to the next by the same angle, whereas the orientation of the calibration sphere is maintained for all four basic measurements. Based on the basic positions, a reference position of the tool spindle relative to the element, at which the tool spindle is located above the calibration sphere and the spindle axis goes through a central point of the calibration sphere, is determined and taken into account in further calibration of the measurement probe.