The known measuring techniques are difficult to apply for determining the power loss of transformer windings at high frequencies. None of them can be used to obtain the distribution of the power loss among and within the layers or discs. Analytical methods use simplification on the geometry of problems, therefore applicable in special cases. In this paper a finite element technique is introduced for calculating the ac losses of disc windings at high frequencies. This includes a method to calculate the ac resistance of windings which not only applicable for any winding with arbitrary shape of conductors, but also gives more accurate answers than analytical methods.