We demonstrate the effect of varying the channel and land width dimensions of an interdigitated flow field experimentally and through computational modeling. Measured polarization curves (overpotential versus current density) are reported for a symmetric cell with a ferrocyanide-ferricyanide electrolyte in aqueous potassium chloride. A two-dimensional, coupled fluid dynamic and electrochemical model is developed to interpret polarization results from the symmetric cell. This model suggests that stagnant fluid zones above the center lines of the interdigitated channels negatively impact cell performance. A three-dimensional computational fluid dynamic model is used to calculate the pressure drop and power losses associated with flowing fluid through these flow fields. The voltage efficiency of the cell, corrected for pumping power losses, is evaluated and reported as a function of channel and land width to identify high-efficiency flow fields. The implications for the engineering of large-area flow fields are discussed. (C) The Author(s) 2018. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 License.