The invention relates to a calibration method for an exposure meter of a microscope (1) in which the ray bundle (4; 7) exiting from the microscope objective (22) is divided in to a first partial ray bundle (8) which is guided to an eyepiece (8) in which a grid-line reticle (24) having a focussing mark is positioned and a second partial ray bundle (4) which is guided to a sensor (10) made of electrooptical pixel elements (12) downstream of which an electronic processing unit is positioned. According to the method a calibration sample (15) having a calibration reference point is arranged on the microscope table (3); by displacing the microscope table (2) the calibration reference point of the calibration sample (15) is moved into a specified positional relationship to the focussing mark of the grid-line reticle (24); in this positional relationship the calibration sample (15) having the calibration reference point is imaged on the pixel elements (12) of the sensor (10); and among the pixel elements (12) of the sensor (10) the pixel element on which the image of the calibration reference point falls is chosen as the reference pixel element for future exposure measurements.