The overall strength of our methodology is its ability to determine the charge transfer coefficient, using a simple model of the interface, without the need for computationally expensive multiple cell size computations or methodological extensions to standard DFT setups. Besides treating ion-electron transfers, it can also be used to determine the electrode potential dependence of polar adsorbates like CO * 2 . Given its ability to determine potential dependence of electrochemical reactions at modest computational expense, we envision its use in developing micro-kinetic models to understand electrochemical mechanisms.