This Calculator was originally on yeastcalc.com, which stopped functioning in January 2014.
After unsuccessfully attempting to contact the owner/author I grabbed a copy from archive.org and posted it here. I work in IT and know enough to do basic HTML editing, but do not know Flash and am not a web developer so it is unlikely that I will make any updates or changes to this site, I mostly put it up since I like using this calculator myself and know others like it as well.
If you would like to contact me, the best way to do so would be to send me a PM on the forum over at HomeBrewTalk. My name there is TallDan.