An undergraduate electrical conductivity measurement experiment in a physical chemistry lab and basic fitting procedures are presented that allow a characterization of micellar system of hexadecyltrimethylammonium bromide (cetyltrimethylammonium bromide, CTAB) in binary mixture of water and acetonitrile (ACN) as a cosolvent (10%, v/v) at 30.0 °C. Conductivity-concentration data were processed by inbuilt function of ORIGIN software to attain the values of critical micelle concentration by method of integration. Acquiring the data-fitting skills that are developed through the addition of a computational tool to a conventional electrical conductometry experiment has a general significance for its applications to more complex upper-level experiments with the aim to process data and perform fast calculations and graphics.