TAPAs is the Toolkit for Accelerator Physics on Androids. It provides a set of interoperative calculations of interest to accelerator scientists and students. These include calculations related to electron storage rings, undulators, synchrotron radiation, electron linear accelerators, electron sources, free-electron lasers, electromagnetism, electrical circuits, and particle passage through matter. The emphasis is on electron accelerators, particularly storage rings with synchrotron radiation.