The combination of interdigitated flow fields (IDFF) with porous electrodes offers lower pressure drop and better performance than conventional flow-through porous electrodes in redox flow batteries. Comprehensive three-dimensional and simplified one-dimensional+two-dimensional models describing flow uniformity and pressure losses within flow through, parallel, and interdigitated flow fields were developed and used to demonstrate the benefits of IDFF. Analytical solutions for IDFF that compare favorably with computational fluid dynamics quantify the trade between pressure loss and velocity maldistribution both along the channels and within the electrode. (c) 2018 American Institute of Chemical Engineers AIChE J, 64: 3746-3755, 2018