Abstract: A machine tool comprises a measuring device, which is arranged on the machine tool, a control device, and a tool unit. The measuring device comprises at least one structure-borne sound sensor. T control device is coupled to the measuring device and to the tool unit. The control device is configured to acquire, by means of the measuring device, structure-borne sound signals caused by the machine tool and to determine a state variable, which describes an actual state of the machine tool, by forming a differential spectrum from a broadband reference spectrum and a broadband actual spectrum.