A poorly operating or perturbed cell in a fuel cell stack can influence the local current density distributions in neighboring cells, which in turn can lead to lower overall performance and lifetime of the stack. In order to quantify the degree of coupling between adjacent cells in a fuel cell stack, steady-state conservation of charge in a bipolar plate between two cells is analyzed, and a dimensionless number is identified. The latter, which provides an aggregate measure comprising the design, operating conditions and material properties of the bipolar plate, is correlated with the current redistribution between cells, and an upper bound is determined. The fidelity of the dimensionless number and its bound are verified with a one-phase non-isothermal proton exchange membrane fuel cell stack model. The number can easily be employed prior to the design of a fuel cell stack in order to minimize coupling of the current density between cells. (C) 2013 The Electrochemical Society. All rights reserved.