Warning! The HST unit conversion tool was replaced by a Jupyter notebook. This incorporates the latest WFC3/UVIS (WFC3 ISR 2021-04) and WFC3/IR (WFC3 ISR 2020-10) photometric calibration as well as recent changes in the Vega spectrum of up to ~1.5% (Bohlin et al. 2020). See Section 9.5.2 of the WFC3 Data Handbook for more information.