In this work, we explore the implementations buck and boost converters using Back-End-of-Line Nano-electromechanical (BEOL NEM) relays, for on-chip voltage conversions in low power applications. We use our custom relay model for simulations, which is validated against an FEA tool. The relay-based DC-DC converters use an inductorless, charge pump topology in a switched-capacitor configuration. We show that both buck and boost converters can be implemented with only four NEM relays and offer minimum output ripple and higher efficiency compared to their CMOS counterparts.