DC-DC power electronics converters are used in many applications such as electrical vehicles, energy storage systems, renewable energy sources. The inductors designed for a specific frequency and current level have significant impact on converter performance. In this study, an inductor is designed for a specific frequency and current value with some common core geometric structures called EE, block, pot and toroidal. Since inductors operate at high frequency values, the Kool-Mu which is a kind of powder core is selected. The Kool-Mu has distributed homogeneous air gaps and is used in inductor designs that saturation is not desired. Inductors are designed for EE core, toroidal core, pot core and block core structures. Electromagnetic modelling of these inductors designed for different core structures are carried out with finite element analysis (FEA), and inductance stability, core and winding losses, mechanical specifications and flux distributions have been reported comparatively. In addition, some suggestions are derived in core structure definitions for DC-DC converter inductor design.