A method for dimensional X-ray measurement, in particular by way of computed tomography, featuring the steps: a) irradiating a test object with non-monochromatic X-ray radiation from a virtually punctiform X-ray source , b) measuring the intensity (I) of the X-ray radiation in the radiation path behind the test object by means of a flat panel detector which has a plurality of pixels (P) to obtain pixel-dependent intensity data (I(P)), and c) calculating at least one dimension (H) of the test object using the pixel-dependent intensity data (I(P)), characterised in that d) the pixel-dependent intensity data (I(P)) is corrected by the influence - of an effective penetration depth ( τ ) in the flat panel detector caused by beam hardening and/or - a displacement of the effective source location (Q) on a target of the X-ray source caused by beam hardening is corrected and the correction comprises the following steps: for at least a majority of the pixels (P) (i) identifying a zero point distance (r) of the pixel (P) from an optical axis (A), (ii) identifying the intensity (I) of the X-ray radiation measured by the pixel, (iii) allocating a corrected position (K') depending on the zero point distance (r) and the intensity (I), and (iv) calculating corrected pixel-dependent intensity data (I') from all corrected positions (K') and the corresponding intensities (I'(P)). a) irradiating a test object with non-monochromatic X-ray radiation from a virtually punctiform X-ray source , b) measuring the intensity (I) of the X-ray radiation in the radiation path behind the test object by means of a flat panel detector which has a plurality of pixels (P) to obtain pixel-dependent intensity data (I(P)), and c) calculating at least one dimension (H) of the test object using the pixel-dependent intensity data (I(P)), characterised in that d) the pixel-dependent intensity data (I(P)) is corrected by the influence - of an effective penetration depth ( τ ) in the flat panel detector caused by beam hardening and/or - a displacement of the effective source location (Q) on a target of the X-ray source caused by beam hardening is corrected and the correction comprises the following steps: for at least a majority of the pixels (P) (i) identifying a zero point distance (r) of the pixel (P) from an optical axis (A), (ii) identifying the intensity (I) of the X-ray radiation measured by the pixel, (iii) allocating a corrected position (K') depending on the zero point distance (r) and the intensity (I), and (iv) calculating corrected pixel-dependent intensity data (I') from all corrected positions (K') and the corresponding intensities (I'(P)). - of an effective penetration depth ( τ ) in the flat panel detector caused by beam hardening and/or - a displacement of the effective source location (Q) on a target of the X-ray source caused by beam hardening is corrected and the correction comprises the following steps: for at least a majority of the pixels (P) (i) identifying a zero point distance (r) of the pixel (P) from an optical axis (A), (ii) identifying the intensity (I) of the X-ray radiation measured by the pixel, (iii) allocating a corrected position (K') depending on the zero point distance (r) and the intensity (I), and (iv) calculating corrected pixel-dependent intensity data (I') from all corrected positions (K') and the corresponding intensities (I'(P)). (i) identifying a zero point distance (r) of the pixel (P) from an optical axis (A), (ii) identifying the intensity (I) of the X-ray radiation measured by the pixel, (iii) allocating a corrected position (K') depending on the zero point distance (r) and the intensity (I), and (iv) calculating corrected pixel-dependent intensity data (I') from all corrected positions (K') and the corresponding intensities (I'(P)). <EOS>