You currently support 1/365 and 1/12 interest calculation types, but not 1/360, which is commonly needed in the U.S.

You support 1/365 payment calculations, but this doesn't work as expected during leap years, where some people need to use 1/366 instead. I think this is called 1/Actual.

Sometimes we get complex payment/drawdown schedules in the form of a Spreadsheet. It would be nice to be able to import those directly from Excel into your application.

Right now you can set payments to the 1st of every month, for example, but this is no good if that day falls on a weekend. It should be automatically adjusted to the following Monday.

Right now you can enter the amortization period as either a number of periods or a payment amount. But the *term* can only be set as a date. It would be easier if you could enter the number of payments instead, to avoid having to do the math by hand.