<prompt> Human: Ive seen many threads where people who are asking for advice mention theyve made additional payments on their installment loan and then discovered that their balance is higher than they thought it should be. Lenders typically arent bound to apply additional payments to the principal and commonly will take the money and do different things with it, such as:1. Apply the additional payment toward the interest owed.2. Consider additional payments advance payments to be applied toward future payments as they come due.If making additional payments is something youre interested in doing, contact your lender and ask them the exact way they want you to send them a payment so it gets applied toward the principal; for example, I had once had an auto loan where in order to make additional principal payments the bank would require I send them a separate check with PAYMENT TOWARD PRINCIPAL written on it. Follow the instructions your lender gives, then follow up with them after theyve processed the payment to ensure it was applied to your principal balance. If it wasnt, call them up and ask why. Unless your loan expressly forbids additional principle payments - which is likely the sign of a bad loan - then you should be able to make them unless your lender is trying to be shady. That aside, kudos to you for wanting to aggressively pay down your debt!  <response>: This is true I know my mortgage requires I put a check mark on what I want them to do with the extra money otherwise it just sits there assumed to be used for future payments. Its part of the reason I pay them through their online system. Because, having my bank send the check would mean calling them every month or not having the money go towards anything.While I could do a paper check myself who does that anymore plus stamps and what just make it a waste of money imo. 