The invention relates to a method for determining a position of a work piece and of a tool in a machine tool, in which a work piece is clamped at the machine tool, in which the tool is subsequently inserted into a rotatable spindle shaft by means of a tool holder and the spindle shaft is set into rotation, in which an electrical voltage is applied between the work piece and the tool, in which the tool and the work piece are displaced with respect to one another, and in which a variation in the applied voltage is determined in the event of a contact between the tool and the work piece, and the respective position of the work piece and/or of the tool is determined and recorded in a computing program for control/regulation of the machining of the work piece.