<p>In this day and age, the emphasis is placed on the efficiency and consumption of all electric devices. In the field of electric motor design, efficiency is one of the most important factors. An important design factor is the losses in ferromagnetic materials. Reduction of iron losses can be achieved by the use of composite materials and low-loss electrical steels. In the design process it is advantageous to have an accurate and computationally inexpensive model available. This paper deals with the comparison of analytical, experimental, and FEM/numerical models. Based on this analysis it is possible to determine the accuracy of computationally inexpensive models and numerical models for the design and optimization phase in electric motors. Models presented in the paper are analytical Steinmetz and improved Steinmetz, loss separation model used in experimental measurements, and numerical FEM model. The results of each model were analyzed and compared with other methods. Subsequently, these results enable the refinement of iron losses calculations, which in turn present us with a better idea of their origin, behavior, and subsequent reduction, resulting in machines with higher efficiency.</p>