Credit Card Payoff Calculator

This calculator follows a credit card balance month by month, charging interest on what is left and rounding to the cent the way a statement does. The first mode pays only the minimum, which shrinks as the balance falls, so it returns the number of months, the total interest and how that interest compares with the balance you started with. The second mode works backwards: give it a deadline in months and it returns the fixed payment that clears the card by then, along with the interest that path costs. You set the APR and the minimum payment rule yourself, because issuers word theirs differently. It assumes no new spending on the card and no fees beyond interest.