Calibration method for a coordinate measuring machine (1,2,3), the coordinate measuring machine (1,2,3) comprising • a drive mechanism for moving a tool carrier (15,55) relative to a base (11,31) for approaching a measurement point and • a calibration laser head (20,21) implemented so and attached to the tool carrier (15,55) so that □ a laser beam, which is emittable by the calibration laser head (20,21), is swivelable around at least two basically perpendicular axes (A,B,C,X,Y,Z) and □ changes in distance are measurable interferometrically by means of the calibration laser head (20,21), wherein a set of retro-reflectors (16a-e,17) is arranged in fixed positions relative to and/or onto the base (11,31) and the method comprises • emitting and directing the laser beam towards a first of the set of retro-reflectors (16a-e,17), whereby a measuring path is defined by the orientation of the laser beam, • moving the calibration laser head (20,21) along the measuring path so that the laser beam is kept directed towards the first retro-reflector according to the measuring path and the reflected laser beam is continuously received at the calibration laser head (20,21), • measuring by using the calibration laser head (20,21) the change in distance to the first retro-reflector at a plurality of measuring positions along the measuring path, • gathering a machine position for each of the plurality of measuring positions, the machine position relating to a position of the tool carrier (15,55) relative to the base (11,31), particularly wherein machine coordinates corresponding to drive positions of the drive mechanism are gathered, and • deriving calibration data for the coordinate measuring machine (1,2,3) depending on the measured change in distance and the machine position for each of the plurality of measuring positions. • a drive mechanism for moving a tool carrier (15,55) relative to a base (11,31) for approaching a measurement point and • a calibration laser head (20,21) implemented so and attached to the tool carrier (15,55) so that □ a laser beam, which is emittable by the calibration laser head (20,21), is swivelable around at least two basically perpendicular axes (A,B,C,X,Y,Z) and □ changes in distance are measurable interferometrically by means of the calibration laser head (20,21), wherein a set of retro-reflectors (16a-e,17) is arranged in fixed positions relative to and/or onto the base (11,31) and the method comprises □ a laser beam, which is emittable by the calibration laser head (20,21), is swivelable around at least two basically perpendicular axes (A,B,C,X,Y,Z) and □ changes in distance are measurable interferometrically by means of the calibration laser head (20,21), • emitting and directing the laser beam towards a first of the set of retro-reflectors (16a-e,17), whereby a measuring path is defined by the orientation of the laser beam, • moving the calibration laser head (20,21) along the measuring path so that the laser beam is kept directed towards the first retro-reflector according to the measuring path and the reflected laser beam is continuously received at the calibration laser head (20,21), • measuring by using the calibration laser head (20,21) the change in distance to the first retro-reflector at a plurality of measuring positions along the measuring path, • gathering a machine position for each of the plurality of measuring positions, the machine position relating to a position of the tool carrier (15,55) relative to the base (11,31), particularly wherein machine coordinates corresponding to drive positions of the drive mechanism are gathered, and • deriving calibration data for the coordinate measuring machine (1,2,3) depending on the measured change in distance and the machine position for each of the plurality of measuring positions.