Method for the multistep calibration of measuring and analysis methods for a portable gas measuring device (1, 1') having a detector unit for gas chromatography for selective detection of a plurality of chemical compounds, having a connected control unit and having a connected analysis unit, wherein, in a first step after production, a factory setting of the portable gas measuring device (1, 1') and/or a device associated with the portable gas measuring device is performed, wherein a database is generated for a plurality of target materials and/or measuring programs for the respective portable gas measuring device, in a second step, a container having a known gas standard is connected to the portable gas measuring device by the user and a reference measurement is performed on this gas standard, in which a multidimensional measured variable is recorded, in particular a gas chromatogram, in a third step, a measuring program for one or more target materials is selected by the user from a list of measuring programs, wherein the measuring programs were installed on the device by the producer or can be prepared by the user, in a fourth step, a measurement is triggered, wherein the control unit executes the measuring method in dependence on the selected measuring program, in which a multidimensional measured variable is recorded, and, in a fifth step, the analysis unit automatically carries out an analysis to identify the target materials present in a sample and the respective concentrations thereof, wherein an algorithm processes multiple input variables, among them the multidimensional measured variable from the measurement on the sample, the multidimensional reference measurement on the gas standard, the values for the target material or the target materials for the respective program, and the factory setting for the portable gas measuring device. wherein, in a first step after production, a factory setting of the portable gas measuring device (1, 1') and/or a device associated with the portable gas measuring device is performed, wherein a database is generated for a plurality of target materials and/or measuring programs for the respective portable gas measuring device, in a second step, a container having a known gas standard is connected to the portable gas measuring device by the user and a reference measurement is performed on this gas standard, in which a multidimensional measured variable is recorded, in particular a gas chromatogram, in a third step, a measuring program for one or more target materials is selected by the user from a list of measuring programs, wherein the measuring programs were installed on the device by the producer or can be prepared by the user, in a fourth step, a measurement is triggered, wherein the control unit executes the measuring method in dependence on the selected measuring program, in which a multidimensional measured variable is recorded, and, in a fifth step, the analysis unit automatically carries out an analysis to identify the target materials present in a sample and the respective concentrations thereof, wherein an algorithm processes multiple input variables, among them the multidimensional measured variable from the measurement on the sample, the multidimensional reference measurement on the gas standard, the values for the target material or the target materials for the respective program, and the factory setting for the portable gas measuring device.