Abstract A numerical bit dynamics model has been developed for the purpose of predicting PDC drill bit performance under conditions of a full-scale drilling simulator test. The model accounts for the interaction of the PDC cutters with the bottom hole and side wall rock surface and bit impact energy loss and friction between the bit gage and hole wall. It also accounts for the induced vibration of the main mechanical components of the full-scale drilling simulator. The model has been validated by comparing predicted bit performance with full scale drilling experiments. Twenty bit designs (15 anti-whirl and five "conventional") ranging from 5 7/8" to 17 1/2" have been used in this validation. The numerical simulator correctly predicts for 18 out of the 20 bits whether or not the bit whirls and the rate of penetration at which the bit stops vibrating in the hole. This paper discusses the development, numerical implementation, and experimental validation of this PDC bit numerical drilling dynamics simulator.