A written computer-based MatLab simulation program was employed to determine the reactivities of a polymeric isocyanate. The program redeems experiments needed for isocyanate characterization. Experimental results of reaction temperature profile and polyurethane gel viscosity were required to verify the simulation program's reaction parameters. Isocyanates reactivity characterization and polyol characterization was done earlier, increasing the accuracy of the reaction temperature results, making polyurethane raw materials optimum selection faster. In the current research, a MatLab computer program was developed to characterize the reactivates of different isocyanates moieties based on para versus ortho isocyanate moieties. This approach assists in predicting the fractional content of isocyanate moieties of unknown polymeric isocyanates. Experimental data, including temperature profiles and viscosity profiles of urethane gel reactions, were used to validate the simulation results. Methylene diphenyl diisocyanate, toluene diisocyanate, and Diethylene glycol were utilized for getting the kinetic parameters. The para-isocyanate moieties were found to be more reactive compared to the ortho-isocyanate moieties.