Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

Prepaying a loan: Shouldn't the interest be recalculated like a shorter loan?
So, let's take a mortgage loan that allows prepayment without penalty. Say I have a 30 year mortgage and I have paid it for 15 years. By the 16th year almost all the interest on the 30 year loan has been paid to the bank This is incorrect thinking.  On a 30 year loan, at year 15 about 2/3's of the total interest to be paid has been paid, and the principal is about 1/3 lower than the original loan amount.  You may want to play with some amortization calculators that are freely available to see this in action.   If you were to pay off the balance, at that point, you would avoid paying the remaining 1/3 of interest.   Consider a 100K 30 year mortgage at 4.5% In month two the payment breaks down with $132 going to principal, and $374 going to interest.  If, in month one, you had an extra $132 and directed it to principal, you would save $374 in interest.  That is a great ROI and why it is wonderful to get out of debt as soon as possible.   The trouble with this is of course, is that most people can barely afford the mortgage payment when it is new so lets look at the same situation in year 15. Here, $271 would go to principal, and $235 to interest.  So you would have to come up with more money to save less interest.  It is still a great ROI, but less dramatic.   If you understand the "magic" of compounding interest, then you can understand loans.  It is just compounding interest in reverse.  It works against you.