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 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 to obtain pixel-dependent intensity data (I), and c) calculating at least one dimension of the test object using the pixel-dependent intensity data (I), characterised in that d) the pixel-dependent intensity data (I) 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 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 (i) identifying a zero point distance (r) of the pixel from an optical axis, (ii) identifying the intensity 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, and (iv) calculating corrected pixel-dependent intensity data (I') from all corrected positions (K') and the corresponding intensities (I'). a) irradiating a test object with non-monochromatic X-ray radiation from a virtually punctiform X-ray source, b) measuring the intensity 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 to obtain pixel-dependent intensity data (I), and c) calculating at least one dimension of the test object using the pixel-dependent intensity data (I), characterised in that d) the pixel-dependent intensity data (I) 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 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 (i) identifying a zero point distance (r) of the pixel from an optical axis, (ii) identifying the intensity 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, and (iv) calculating corrected pixel-dependent intensity data (I') from all corrected positions (K') and the corresponding intensities (I'). - of an effective penetration depth ( τ) in the flat panel detector caused by beam hardening and/or - a displacement of the effective source location 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 (i) identifying a zero point distance (r) of the pixel from an optical axis, (ii) identifying the intensity 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, and (iv) calculating corrected pixel-dependent intensity data (I') from all corrected positions (K') and the corresponding intensities (I'). (i) identifying a zero point distance (r) of the pixel from an optical axis, (ii) identifying the intensity 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, and (iv) calculating corrected pixel-dependent intensity data (I') from all corrected positions (K') and the corresponding intensities (I').