measurement
LIVEUnit conversion that runs entirely in this tab and rounds honestly.
in-browser utility
Runs entirely in this tab. No network.
Length, mass, volume, temperature, data, and time. It converts in the page, with no network call, and it rounds to a sensible number of significant figures instead of spraying fifteen decimals at you.
The library underneath is small and standards-correct on purpose. A converter is the kind of thing everyone assumes is trivial until they hit floating point, customary versus metric ounces, and the difference between a kilobyte and a kibibyte. Those are the interesting parts, so that is where the tests are.