Inductor is one of the most widely used high frequency magnetic components in power electronic devices. The presence of air gaps in inductor avoids core saturation at low currents, but meanwhile puts challenges on the winding losses calculations due to the effect of fringing fields. Prior studies either overlook the influence of air gaps or focus on the fringing fields of regularly constructed air gaps, leaving out research on the impact of complicated and irregular air gaps. This paper uses a semi-analytical approach to predict the winding losses in gapped inductors by putting forward a revised coefficient. More potential affecting factors could be addressed in the calculation by using the proposed approach. Additionally, the approach can predict the winding losses in inductors under the case of irregular air gaps, which further broadens its application in real cases.