This paper presents simple mathematical expressions that can be used for optimizing fuel cell electrode structures, specifically polymer electrolyte membrane fuel cells (PEMFCs). Based on the effectiveness factor, equations relate current density to catalyst utilization and a mass transfer coefficient. These can be used to screen new materials or identify which specific processes need to be improved in an existing electrode design. The optimum thickness, or catalyst loading, and maximum current that can be achieved with a given set of materials can be calculated from a simple set of equations based on the mass transfer characteristics of the electrode materials. These methods can save considerable experimental time and cost during electrode development.