Below is a simple loan amortization calculator implemented in JavaScript. It's primarily intended to be used for home mortgages. To see the source code, or to make a comment, visit

This doesn't qualify as professional financial advice, by the way. I tested some scenarios against a similar calculator, on, and while the numbers didn't match exactly, they were only ever off by a few cents. That's close enough for my purposes, but I'm told that creditors can be surprisingly petty about a couple of cents sometimes, so be careful.