Traditionally, steel joints are calculated by the calculation rules described in the Eurocode 3: NEN-EN 1993-1-8. Effective lengths are important parameters to determine the different resistances of the components in the steel joint. Finite Element Analyses (FEA) are becoming increasingly important in engineering, including in construction industry. Specialised software is developed to determine the stresses and corresponding strains in the plate elements of the joints by the Finite Element Method (FEM). This thesis reports on a comparative study of the traditional calculation method and a method which is using partial FEA for determining the resistance of joints. The approach, assumptions and principles used for these calculations are explained in this report. It will be investigated whether the same components of a joint are decisive for each method and if there are differences in joint resistances. If so, the magnitude of the difference will be determined as well. This is done for different simple shear joints (SSJ) and moment resisting joints (MRJ). For the last group, two joint configurations (Flush End Plate Joint and Extended End Plate Joint) are calculated manually, partially modelled with the FEM, and compared with the results of executed experiments.