PURPOSE: To measure the length of sheets in a printing press by a method wherein a control device connected to a running sensor includes a calculation circuit for pulses of a rotation signal generator which are taken into the device between side edges of a leading edge signal and a trailing edge signal and the length of sheets being fed can be sensed by means of a noncontact means.

CONSTITUTION: A rotation signal generator 7 generates pulses 11, e.g. pulses of 4096 every one revolution. And a target value 12 for the leading edge of a sheet 1 and a target value 13 for the trailing edge of the sheet 1 stored in a control device 9 are connected with signals 14, 15 of two sensors 10 respectively, whereby the length (1) of the sheet is obtained. In an embodiment, the length (1) has an expansion of an increment 11 over 3476 of the generator 7. In this case, in the target length of sheet, two increments 11 or length Δ1 lacks. In this case, the sheet is cut to extremely short length, and hence a corresponding impression cylinder is contaminated or in the case of a perfecting press, the sheet cannot be transferred any longer.