I know that excel has a function call CUMIPMT() that will return the
total interest paid on a loan given a rate, initial value, and range
of periods that you want to find the sum in. Is there a function out
there; however, where I can provide the monthly payment also. I'm
wanting to see how much interest I save over a period by making extra
payments on the principal and want to do it with a function rather
than expanding everything out in an amortization table. Does anyone
have any suggestions on how to do this or where I can go to find out
more. Thanks.