Planar spiral inductors on silicon substrates were optimally designed using MATLAB, which is a tool to perform numerical computations with matrices. The equivalent circuit parameters of the spiral inductors were extracted from the data measured from the spiral inductors fabricated using a 0.18 $mu extrm{m}$ RF CMOS process. The metal width, which is a critical design parameter, was optimized for the maximum quality factor with respect to the operating frequency.