The invention relates to a method and device for calibrating a measuring instrument with at least two partial systems (K;M), which can be displaced with regard to one another, and with means for generating an image of at least one first partial system (K) on at least one detecting component (A) of at least one partial system. The invention provides that after establishing a mathematical model, a parameter set, which quantifies influencing factors on systematic measurement errors of the measuring instrument and which has at least one parameter, is derived from the mathematical model. Afterwards, the imaging of the structure elements (S) of a first partial system (K), said structure elements determining the relative position of a partial system, ensues on a second partial system (M). The image of the structure elements (S) of the first partial system (K) is converted into signals by the detecting component (A), and at least one signal vector is recorded. Correction values, which reduce systematic measurement errors of the measuring instrument, are derived from the estimated values of the parameter set and made available.