Full schedule with extra-payment what-ifs.
Open the Loan & Mortgage Amortization tool →Your scheduled payment is the level amount that pays the loan to zero over its term: each month interest is charged on the remaining balance and the rest of the payment chips away at principal. We total the interest you pay across the whole loan from that exact month-by-month schedule.
Paying a little extra each month goes straight to principal, so the balance falls faster and less interest accrues. We run the same schedule with your extra payment to show how much interest and how many months it saves. The rate is your loan's own terms, so there is no rule to cite, just the arithmetic.
Computed entirely on your device for U.S. taxes and benefits. Nothing is ever sent anywhere, and it is free forever. Educational information, not financial, tax, investment, or legal advice.