Method for calibrating an absolute displacement measurement device of a spindle actuator for a hydraulic master unit, the spindle actuator having at least the following components: - a drive spindle which has a plurality of thread turns with a defined thread pitch for the translational movement of a spindle nut, the drive spindle having a first measuring magnet at a first angular position of the drive spindle, and the spindle nut having a predetermined maximum displacement travel between a starting position and an end position; - a measuring shaft having a second measuring magnet at a second angular position of the measuring shaft, it being possible for the measuring shaft to be driven by the drive spindle in a fixed transmission ratio with the drive spindle, the transmission ratio relative to the measuring shaft being configured in such a way that the periodicity of the measuring shaft corresponds to a complete revolution of the drive spindle multiplied by the sum of an arbitrary first integer (m) and the reciprocal of a second integer, the second integer having a greater magnitude than the number of the thread turns of the drive spindle; - a first angle sensor for detecting a first angle measurement signal from the first measuring magnet by using a first magnetic field; and - a second angle sensor for detecting a second angle measurement signal from the second measuring magnet by using a second magnetic field, the method having at least the following steps: a. defining a single first angular position of the first measuring magnet for each complete revolution of the drive spindle as a turn change; b. detecting the second angle measurement signal at at least one adjacent turn change; c. storing the second angle measurement signal as a calibration value assigned to the at least one adjacent turn change, in particular a translational absolute displacement position of the spindle nut being determined on the basis of the unambiguously determined thread turn with the aid of the mechanical relationship between the respective thread turn and the translational absolute displacement position of the spindle nut, characterized in that the second measuring magnet exerts at most such a negligible influence on the first angle measurement signal that the first angle measurement signal is unambiguous, and wherein the first measuring magnet influences the second angle measurement signal in such a way that the second angle measurement signal is ambiguous, wherein, in addition, at least the following steps are carried out: a'. travelling through the individual thread turns of the drive spindle; b'. at each turn change, detecting the second angle measurement signal; c'. storing the second angle measurement signal as a calibration value assigned to the respectively adjacent turn change. - a drive spindle which has a plurality of thread turns with a defined thread pitch for the translational movement of a spindle nut, the drive spindle having a first measuring magnet at a first angular position of the drive spindle, and the spindle nut having a predetermined maximum displacement travel between a starting position and an end position; - a measuring shaft having a second measuring magnet at a second angular position of the measuring shaft, it being possible for the measuring shaft to be driven by the drive spindle in a fixed transmission ratio with the drive spindle, the transmission ratio relative to the measuring shaft being configured in such a way that the periodicity of the measuring shaft corresponds to a complete revolution of the drive spindle multiplied by the sum of an arbitrary first integer (m) and the reciprocal of a second integer, the second integer having a greater magnitude than the number of the thread turns of the drive spindle; - a first angle sensor for detecting a first angle measurement signal from the first measuring magnet by using a first magnetic field; and - a second angle sensor for detecting a second angle measurement signal from the second measuring magnet by using a second magnetic field, a. defining a single first angular position of the first measuring magnet for each complete revolution of the drive spindle as a turn change; b. detecting the second angle measurement signal at at least one adjacent turn change; c. storing the second angle measurement signal as a calibration value assigned to the at least one adjacent turn change, a'. travelling through the individual thread turns of the drive spindle; b'. at each turn change, detecting the second angle measurement signal; c'. storing the second angle measurement signal as a calibration value assigned to the respectively adjacent turn change.