A round baler is equipped with a bale compression chamber, a roller, which is supported against the frame of the round baler so as to be rotatable and, during the formation of the bale, so as to be otherwise essentially stationary and which directly or indirectly interacts with the bale, and a sensor for detecting the size of a bale forming in the bale compression chamber. The sensor is configured for detecting the supporting force with which the roller bears against the frame.
