The present invention relates to a method for measuring the diameter and/or the geometry of the diameter of a cylindrical object. The cylindrical object has a longitudinal axis and a cylindrical shell. The method comprises measuring in a contactless manner at a specific point in the direction of the longitudinal axis the momentary circumferential velocity of the cylindrical shell at specific time or the distance which the circumference of the cylindrical shell rotates, measuring revolutions of the cylindrical shell or the angle of rotation of the cylindrical shell simultaneously with the measuring of the momentary circumferential velocity at specific time or the distance which the circumference of the cylindrical shell rotates, and calculating the diameter of the cylindrical shell and/or the geometry of the diameter of the cylindrical shell at the specific point in the direction of the longitudinal axis. The present invention also relates to a measurement system for measuring the diameter and/or the geometry of the diameter of a cylindrical object and the use of the measurement system.