A heterogeneous electrode surface has been modeled using a regular distribution of circular anodes in a surrounding coplanar cathodic matrix. In the absence of mass transport effects, galvanic currents and potentials have been calculated using finite‐element analysis, with nonlinear electrode kinetics. For a fixed ratio of anodic to cathodic areas on a heterogeneous surface, calculated galvanic currents increase linearly with the active perimeter between cathodic and anodic regions. Furthermore, the current is independent of the shapes and distributions of anodic regions in a surrounding cathodic plane provided that the ratio of overall anodic area to active perimeter is conserved. Thus, due to its longer active perimeter, a surface represented by a large number of tiny anodic islands dispersed in a cathodic sea will exhibit much greater galvanic currents than an equivalent surface represented by a small number of large anodic continents.