This is really rough right now but it should get more polished as I work on it and get feedback. I coded this script because I got tired of doing the math the hard way with a calculator, and I had a hard time finding any online calculators that did exactly what I was looking for. I'm still working out some kinks and playing around with what I can do. I'd appreciate any comments anyone has and I hope a few people find this useful.

Please leave your comments on my blog at Praetorian.nutang.com. Thanks.
- David

In case you're interested in the math, the formula for this is : balance * interest / 365 = interest earned per day. When calculating for the month be sure to subtract weekends and holidays.