Abstract: A round baler includes a baling chamber and a press means mounted within the baling chamber. A first sensor is disposed within the baler for sensing data related to a change in a diameter of a bale being formed in the baling chamber. A second sensor is configured to detect data related to a speed of the press means, such as a rotational speed of a drive shaft. The data related to the change of the diameter of the bale and the data related to the speed of the press means after each rotation of the bale are processed to determine a thickness of a layer of the crop material in the bale. The thickness is indicated in a display unit for an operator to view.