Interest in ammonia as an energy carrier is growing due to its superior storage and transport properties compared to hydrogen. The objective of this work is to construct a useful tool for predicting the behavior of a solid oxide fuel cell (SOFC) stack fed directly with ammonia. This configuration is particularly interesting because the internal cracking of ammonia eliminates the need for an external cracker, thus reducing the overall cost of the system. The ammonia decomposition reaction was implemented in the anode channel of the stack and calibrated against literature results. The model was then validated in the ohmic region only by calculating the area specific resistance (ASR) and comparing the results with experimental data collected at the Bruno Kessler Foundation (FBK) laboratory. This SOFC model can therefore be used as a starting point for the analysis of a scale-up application.