I am pleased to announce that the NumericalChameleon 2.0.0 is on the web:
The NumericalChameleon is free, open source, cross platform and
comprehensive software in order to convert units with a precision of up
to 1000 decimal places. It supports more than 5200 units in 93 categories, including not only all important physical units, but also useful units in non-standard categories like exchange rates, time zones, spoken numbers (literally and by audio), roman numerals, geographic coordinates, radixes, fractions, checksums, bits&bytes, screen resolutions, colorcodes, unicodes, international dial codes, calendar and holiday calculations and many more.
Release notes for the version 2.0.0 are at