This paper presents an improved model for pressure drop in a honeycomb monolith reactor, which configuration is widely used in automotive exhaust gas after treatment systems. The model is based on pressure drop simulations for single channel models complemented with large eddy simulation. The model has multiple zones, and accounts for the pressure losses for flow entering, passing through, and leaving the substrate. The new multi-zone model is theoretically more consistent than those that use a single permeability for the whole the monolith, and it gives a superior result for pressure drop and hence flow distribution. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.