Converting the frequency is needed in many fields of advanced technology. “Electric circuits” or “coupled motors and generators” are usually used for frequency conversion. This article introduces a new piezoelectric frequency converter (PFC), using an idea similar to piezoelectric transformers (PT). PFC uses two piezoelectric discs as input and output elements which are pushed together. There is a common electrode between these two elements and two electrodes input and output on the other sides. When the input disc is forced to vibrate in the out-of-plane mode, the output disc vibrates in its radial mode. By applying different input frequencies, different output frequencies can be obtained. However, the input and output frequencies are limited to the piezoelectric element’s out-of-plane and radial modes. Therefore, the proper size of piezoelectric discs should be used to get the necessary gain. Simulation and experiments show that the mechanism works as predicted, and their results are in good agreement. For the chosen piezoelectric disc, the lowest gain increases the frequency from 61.9 to 118 kHz, and the highest gain increases the frequency from 3.7 to 51 kHz.