In this work, a computationally affordable macroscale model is developed to simulate the instantaneous collection efficiency and pressure drop of pleated depth filters. The numerical scheme presented here allows for the deposition of particles inside the fibrous fabric of a pleated filter, and accordingly varies its permeability and capture efficiency to simulate aging of the filter over time. This has been accomplished by developing a series of in-house subroutines that remarkably enhance the capabilities of the commercially available computational fluid dynamics code from ANSYS. This model is used to quantify the influence of pleat count, particle diameter, and flow velocity on the instantaneous performance of pleated filters with V-shaped pleats. Our results indicate that increasing the number of pleats reduces the rate of increase of a filter's pressure drop and capture efficiency. Predictions of our model have been compared against available experimental data, and good agreement has been observed. (C) 2012 Elsevier B.V. All rights reserved.