I saw someone make one on basil so me and a couple of friends (@MoldyBunny; @iAmFear; and someone else) decided that we could all probably do better and we decided to make our own calculators to find out stuff.
I was the only one who did end up finishing it as of this post so I'm posting it here. It is open source.
Compiled w/ Visual Studio 2010 Ultimate.
Current Version: v1.4 (June 3rd, 2012)