The use of pre-calculated duty cycles for power factor correction leads to a significant simplification of the design and a reduction of the final cost. There are previous proposals for handling non-nominal conditions such as input voltage or load variations in pre-calculated power factor correction. However, there are no proposals for handling input frequency variations for this kind of pre-calculated duty cycles controllers, which have an important impact in the power factor even if they are small variations. This paper measures this impact and includes two alternative solutions to handle the variations of the input frequency. The results show that the introduction of either of these solutions keeps the power factor values over 0.991 and the input current total harmonic distortion below 11.33% for an input frequency range from 48 to 52 Hz.