In this study, bonded-particle models were used to simulate the intact rock behavior of Westerly granite. Two three-dimensional models were tested: the enhanced bonded-particle model (EBPM) and the flat-joint contact model (FJCM). To calibrate both models, a new standard procedure was developed. The results of the simulations of the models were compared with the intact rock behavior determined by laboratory tests, including elastic parameters, peak and threshold envelopes, and postpeak behavior. From this study, it can be concluded that the FJCM better represents the mechanical behavior of Westerly granite rock, especially at the low to intermediate confining pressures. Based on this work, it is recommended to use the FJCM to model the behavior of brittle rock at the low to intermediate confining pressures.