Current safety mechanisms implementing industry standards for human-robot coexistence separate humans and robots through caging. Other approaches allowing humans to enter the workspace of manipulators do not provide formal safety guarantees. Thus, this study aims to facilitate the widespread adoption of collaborative robots by presenting SaRA, an extensible tool that performs set-based reachability analysis and formally guarantees safety. Our experimental results show that the set-based prediction of a human can be computed in a few microseconds, using SaRA, allowing for real-time consideration of many surrounding humans in an environment.