Mismatch of solar cells that occurs during fabrication of the modules can lead to unavoidable power losses. However, it is difficult experimentally to identify incidences of power loss from solar cells that behave similarly due to measurement error. Power loss in a module is mainly affected by three mismatch factors: photocurrent, series, and shunt resistance levels. An equation to determine the output of a partially mismatched module using only the photocurrent and series resistance has been published. Here, a newly developed model that considers mismatch factors, including the shunt resistance, is proposed. The newly developed model was validated through a comparison of simulation results to the measured output of a module that includes solar cells with different low shunt resistances (within 0.4 A deviation for the output current of the module). The model was then applied to calculate the power loss occurring in a module according to minute differences between the three mismatch factors. Finally, we confirm that the maximum power, as well as the photocurrent, of solar cells should be considered to minimize cell-to-module conversion loss at the module production stage. (C) 2016 Published by Elsevier Ltd.