Purification of hydrogen using polymeric membranes has attracted much attention recently. In this paper, a predictive permeability model was developed for polymeric membranes used in gas separation applications. For calculation of gas solubilities in the membrane at feed-membrane and permeate-membrane interfaces, the compressible regular solution (CRS) theory is employed. The effective concentration-averaged diffusivity was evaluated by using a coupling of the Duda's free volume theory and the modified Speedy model. The detailed step-by-step procedure of application of the developed method was provided and the model was validated using a substantial number of penetrant gas polymeric membrane pairs. The explicit equations of the model and the availability of data for the model input parameters (lattice fluid parameters) make the application of model computationally feasible and straightforward. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.