This work is aimed at development of complex tool using semi-mechanistic mathematical model of steam-cracking process for industrial daily balancing utilization. Models of different types of feedstock were compiled together into universal simulation tool. Models for steam cracking of ethane, LPG, and naphtha used real composition, the model for gas-oil and the hydrocracking product used substitutive composition derived by unique procedure. The model was used to simulate industrial steam cracking unit of ten crackers over a several months period. Simulation results were compared to measured product balance and used for evaluate the model performance.