An arrangement and method for calibrating a spectrometer with a spectrometric apparatus for measuring spectral fractions of the substance to be examined as well as with a calibration unit. The calibrating of the spectrometric apparatus and/or measurement data based on measured spectrometric data is performed, by the following steps: a) measuring a totality of spectral fractions of the substance to be examined; b) storing the totality of the measured spectral fractions in a memory module in the form of a multidimensional coefficient vector; c) automatic extracting, from the totality of the measured spectral fractions physically relevant for the particular measuring procedure via an automatically running, iterative, estimation method furnished in the calibration unit; and d) calibrating the measured spectrometric measurement data for the investigated substance based on the step c) extracted, spectral fractions of the spectrometric data physically relevant for the substance to be examined.