- Upper bounds are derived for the work that can be extracted from simple isothermal chemical converters (chemical engines) that operate from a finite chemical potential reservoir. The incremental gains that stem from adding an arbitrary number of engines is derived. Results are analogous to those for heat engines fed by a finite heat capacity reservoir. Systems of practical interest include chemical reactions, electrochemical cells, and solid‐state converters. The effectiveness of introducing more engines to utilize unexploited chemical potential is expressed in terms of the specific relation between mass transfer and chemical potential difference, often referred to as the device’s current‐voltage curve.