In a method for determining whether a machine tool with a numerical control system for machining a workpiece has warmed up, axis data are obtained which relate to a position of a tool of the machine tool. An indication value is calculated therefrom. It is then determined whether the indication value reaches a predefined threshold value. Furthermore, it is determined whether the machine tool has warmed up, wherein reaching the indication value of the threshold value indicates that the machine tool has warmed up. A method and a machine tool machines workpieces, a computer program product instructs the machine tool, a computer-readable medium stores the computer program product, and a method machines workpieces by the machine tool.