A key theory in concrete mix design is maximizing aggregate packing density (PD) of aggregate mixture. Different methods have been presented by researchers to estimate PD of aggregate mixture. One such method is computer simulation that has become increasingly common over the last decade; however, it is usually a time-consuming procedure. In the current study, a method based on computer simulation is proposed for estimating aggregate PD. In this method, aggregates with specific shapes, grading and PDs are substituted by monosized spherical aggregates. An equation is also presented for determining the diameter of equivalent monosized aggregates. The coefficient of friction between the equivalent monosized aggregates is determined in a way that the monosized aggregates will have a PD equal to that of actual aggregates. The proposed method is also used to simulate laboratory experiments conducted by the present authors and other researchers. Comparisons reveal the high accuracy of the proposed simple method in predicting the PD of aggregate mixtures. (C) 2017 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.