In this study, the effects of bisphenol A (BPA) and diphenyl carbonate (DPC) molar ratio, on the properties of melt-polymerized polycarbonate (PC) were investigated. The molecular size distribution theory proposed by Flory was applied, to melt polymerization of PC to predict physical properties, affected by the molar ratio of BPA and DPC. A terminal OH group affected the viscosity of PC at high temperatures, leading to instability during processing. With increase in the DPC/BPA molar ratio, terminal OH content decreased, albeit different from the theoretical predicted value, because of the volatilization of DPC. Additionally, BPA residual amount was affected by BPA and DPC molar ratio. BPA is regulated in countries because of its similarity to estrogen, and BPA residues can be predicted and managed by using the Flory equation.