A comprehensive three-dimensional fully coupled thermo-electro-mechanical finite element framework is developed for modeling spark plasma sintering (SPS). The finite element model is applied to the simulation of spark plasma processing with four different tooling sizes and various temperature regimes. The comparison of modeling and experimental results shows that the model is reliable for qualitative predictions of the densification behavior and of the grain growth in powder specimens subjected to SPS with a given temperature regime. The conducted modeling indicates the possibility of changing the heating pattern of the specimen (warmer central areas of the specimen's volume and cooler outside areas or vice versa) depending on the size of the tooling. High heating rates and large specimen sizes elevate the temperature and, in turn, material structure gradients during SPS processing. The obtained results suggest that the industrial implementation of SPS techniques should be based on the predictive capability of reliable modeling approaches.