Loan Calulator: Monthly repayment and interest breakdown

Wondering if your loan repayment calculations have been performed correctly this month, taking into account interest rate rises and extra repayments? You might be interested in giving my monthly loan calculator a go.

As my home loan provider doesn't show balances online, and only sends statements every 6 months, I like to ring up every month or two to make sure things are on track. I used to calculate interest, new balances etc in a spreadsheet / calculator but spent an afternoon writing a little Rails app to calculate it for me. Hopefully my little monthly loan calculator is of some use to you too.