We present numerical studies of the flow profile and electrode currents for the hydrogen oxidation and oxygen reduction reactions in an electrochemical flow cell. Koutecký-Levich type equations are obtained by partitioning the electrode surface into flow profile regimes and their correlation to idealized wall-jet and channel electrode geometries. The precision of several Koutecký-Levich type equations is evaluated and it is shown that differences between the most commonly applied equations are negligible within the range of flow rates studied and are surpassed by experimental errors.