This paper presents a comparative study between different buck converter layouts in order to show its impact on conducted disturbances. Indeed, all the stray elements, such as resistive, inductive and capacitive effects, should be considered to obtain an accurate layout model. For this, a numerical approach, that takes into account all parasitic parameters especially capacitive effects, is proposed. In this work, five different layouts were designed and modeled using Advanced Design System (ADS) and ANSYS Q3D extractor softwares. Then, the obtained 3D models are imported into Simplorer circuit-type software to simulate the electrical behavior of the converter. Conducted emissions received by the Line Impedance Stabilization Network (LISN) are extracted to predict the impact of the layout on conducted disturbances. Finally, simulation results are compared for different layouts in the frequency domain.