The stray capacitance of inductors impairs their high frequency impedance. A semi-analytical model is proposed for inductors with conductive core to gain insight for ways to decrease stray capacitance for high frequency power electronic applications. First the elementary capacitances are simulated thanks to 2D electrostatic finite element method (FEM), then an energetic approach is used to compute the global stray capacitance. Experimental verification has been performed on a nanocrystalline ring core. Relative error to the measurement shows that the proposed model improves the accuracy, notably by properly taking into account spaces between turns and between turns and core.