<prompt> Human: Lets assume a mortgage of 80k with an interest of 5.537;. If a check were written to pay it off right now, is any money being saved? The remaining balance of 80k includes interest as well, but would a check written for the balance today decrease the principle and therefore the related interest? Not sure how this works.Assistant: That 80k is unpaid principal balance no interest included. Youll save the interest that youd pay if you have an ongoing balance until maturity date. Human: One more question - if I had 20k lying around, itd be a good idea to reduce that principle since thered be less to pay interest on, right? I was thinking of doing all of it at once in a few years, but it feels like if I did it in chunks sooner itd be a better move.  <response>: Yes that would save you in interest paid and youll pay the loan off faster. Depending on how your finances are sitting it might be a good idea or not. 