In this scientific work, an analysis of surface roughness measurements was performed with the aim of determining the correlations (equations) for calculating 3D roughness parameters. The obtained formulas will enable to predict the values of roughness parameters and make conclusions about the surface exploitational characteristics. In the given work, surfaces with irregular roughness were investigated, i.e. flat grinded, cylindrically grinded, polished, lapped etc, using the modern measuring equipment Taylor Hobson Talysurf Intra 50 and the data processing software µultra. The second and most important task of this work was the analytical calculations of 3D roughness parameters using the random field theory and its basic principles. The calculations were performed on the parameters Sa, Sp, Sdr, Sdq, Spc, Vm, Smr, which are standardized in ISO 25178-2:2012. After the calculations, the results were compared with the measurement data. The differences in the values of the roughness parameters were ≤10 %, but in some cases the error exceeded 10 %, which could be explained by possible surface defects or insufficient measuring area.