This paper discusses the quantification of parasitic components inherent in printed circuit board (PCB) wiring, which can be of considerable value in power conversion circuits. The influence of parasitic inductance and mutual coupling are evaluated in terms of electromagnetic compatibility (EMC) for the switching operation of power MOSFETs in a dc-dc buck converter. The parasitic components are identified based on the partial element equivalent circuit (PEEC) method and modeled with circuit simulation. The estimated effect of the parasitic component on the switching operation of a power MOSFET is validated by comparing it with experimental results.