Analysis of the operation of CMOS gates is a complicated procedure. These gates can be replaced by equivalent inverters and therefore the expressions for the inverters are used to determine the electrical characteristics of the gates. In this paper, the equivalent inverter approach for replacing CMOS gates is evaluated. The NAND gate is used for this evaluation. Parametric expressions are created to determine the transistors widths of the equivalent inverter. A systematic method is used for incorporating the parameter dependencies in the expressions. Results verify the accuracy of this approach.