In testing two important factors which are used to check the complexity level of the CUT (Circuit under Test) is COM (Controllability and Observability Measures). Normally for their calculations standard formulas are exist. But these formulas are different for combinational and sequential circuits. Also to carry out calculation manually for all elements in a complex circuits is very tedious job. To resolve this problem user libraries are developed and embedded in to Simulink. Then a GUI (Graphic User Interface) is developed in MATLAB as a front-end for the designed COM calculation models....