Studies on the washing process have been mainly conducted experimentally, and only a few numerical approaches have been studied. Previous numerical studies on the washing process have focused on analyzing the dynamic behavior of laundry; however, no study has been reported on the detergency caused by the dynamic behavior of laundry. In this study, we predicted the detergency due to the dynamic behavior of the fabrics in a front-loading washing machine using discrete element method simulations and compared the prediction with that of the washing experiments. In addition, the agreement between the experimental and simulated detergencies was high, with a correlation coefficient of 99%. The detergency in the experiment was successfully predicted with power consumption of laundry calculated by the simulations. The lower detergency for larger amounts of fabric was mainly due to reduced normal contact. This study describes the first framework for front-loading washing machine simulations using the discrete element method.