Method for the non-invasive capacitive measurement of the filling level of a filling medium in a container, wherein the method comprises the following steps: a) providing a device for the non-invasive capacitive filling level measurement of a filling medium in a container, said device having I) at least two vertically extending measurement electrodes, which are arranged horizontally one above another and define a measurement surface with a vertical extent, and II) at least one reference electrode, which defines a reference surface with a vertical extent, wherein each measurement electrode together with the reference electrode forms in each case one capacitor so that an electric field is able to be formed in each case, wherein the vertical extent of the reference surface corresponds at least to the vertical extent of the measurement surface, and arranging the device from the outside at or in the immediate vicinity of an external wall of the container; b) measuring the capacitances of the at least two capacitors; and characterized in that the method comprises the following step: c) validating the measurement values by comparing the measurement values with stored calibration values and the measurement values with one another, wherein the measured capacitances are correlated with one another by ratio ascertainment, wherein the measurement values of the at least two measurement electrodes are compared with one another and are correlated with one another, and wherein a correction factor is ascertained on the basis of a measurement electrode that is covered entirely with the filling medium, and all the measurement values of the other measurement electrodes are multiplied by that correction factor. a) providing a device for the non-invasive capacitive filling level measurement of a filling medium in a container, said device having I) at least two vertically extending measurement electrodes, which are arranged horizontally one above another and define a measurement surface with a vertical extent, and II) at least one reference electrode, which defines a reference surface with a vertical extent, wherein each measurement electrode together with the reference electrode forms in each case one capacitor so that an electric field is able to be formed in each case, wherein the vertical extent of the reference surface corresponds at least to the vertical extent of the measurement surface, and arranging the device from the outside at or in the immediate vicinity of an external wall of the container; b) measuring the capacitances of the at least two capacitors; and characterized in that the method comprises the following step: c) validating the measurement values by comparing the measurement values with stored calibration values and the measurement values with one another, wherein the measured capacitances are correlated with one another by ratio ascertainment, wherein the measurement values of the at least two measurement electrodes are compared with one another and are correlated with one another, and wherein a correction factor is ascertained on the basis of a measurement electrode that is covered entirely with the filling medium, and all the measurement values of the other measurement electrodes are multiplied by that correction factor.