Auto Loan Early Payoff Calculator View Calculator Use this calculator if you are paying on a loan and would like to know how much additional you should add to each monthly payment to pay it off in a certain number of years and months. Enter your loan balance, your current monthly payment amount, the interest rate, and the number of years and months to have it paid and this calculator will show you how much additional you must pay each month to meet that payoff time. Learn more about putting this calculator or other calculators on your website.