A new method is presented for calculation of the maximum magnetic force of magnetic ceramics, based on their crystalline structure. The results of this model for the magnetic forces of barium and strontium ferrites are compared with experimental values. In this comparison, the experimental values are less than the values determined by the theoretical model for various magnet cross-sectional areas. This difference is due to the presence of crystal imperfections and incomplete alignment of the magnetic domains. In addition, the magnetic forces of barium and strontium ferrites are a sensitive function of their heat treatments.