The main objective of this study is to obtain three-dimensional empirical K-shell x-ray fluorescence cross-section ( σ K α , σ K β and σ K tot ) values for a wide range of elements 16 ≤ Z ≤ 92 for photons with energies from 5.46 keV to 123.6 keV, using more than 3300 experimental data values published between 1985 and 2023 by numerous researchers. These data values are fitted using an interpolation method including a three-dimensional function against atomic number Z and excitation energy E, resulting in a three-dimensional plot to estimate empirically a three-dimensional set of K α , K β and K tot x-ray fluorescence cross sections. The results of this empirical calculation are compared, for selected elements, with other empirical and experimental values reported in the literature, and a reasonable agreement is observed.