A device and method are provided that enable calibration information to be determined for an x-ray apparatus that performs a three-dimensional x-ray scan. The calibration information is determined using an adapting method, wherein the adapting method is based on a position of an x-ray source relative to an x-ray unit marker device during image acquisition, an x-ray unit data set that describes the position of the x-ray unit marker device during image acquisition, and a two-dimensional calibration data set that describes at least one and preferably two actual two-dimensional x-ray images produced by irradiating a calibration object.