The Peak Stress Method (PSM) is a FE-oriented local approach to evaluate the notch stress intensity factors. In fatigue design welded structures, the PSM allows to estimate the fatigue lifetime of steel welded joints under constant amplitude (CA) loads and has been previously validated against more than 1300 experimental data. However, real engineering welded structures are generally subjected to complex variable amplitude (VA) multiaxial loads in service. Accordingly, the PSM has been recently re-formulated to account for VA uniaxial as well as multiaxial loadings. To this purpose, the PSM has been combined with Palmgren-Miner’s Linear Damage Rule and the extended formulation has been successfully validated against a large bulk of VA fatigue data available in literature. Moreover, an automated analysis tool has been recently developed in Ansys® Mechanical, taking advantage of Ansys® Customization Toolkit, in order to support the FE analyst in the fatigue design of welded structures according to the PSM. The automated algorithm, which was initially developed to analyze structures subjected to CA loadings, has been extended in the present investigation to implement the newly developed multiaxial VA formulation of the PSM. As an output, the automated tool generates fatigue life edge-contour plots and graphs in Ansys® Mechanical, allowing the analyst to rapidly single out the most critical point in the structure among all competing crack initiation sites. The present investigation offers a deeper insight on the automated fatigue strength assessment of steel welded details subjected to VA loadings, according to the PSM.