How the credit card payoff calculator works
Credit card interest compounds on the outstanding balance each month. This calculator converts your APR to a monthly rate, then either counts how many months a fixed payment takes to reach a zero balance, or solves the amortization formula for the payment needed to clear the balance within a target number of months.
Paying down high-interest debt
Because interest is charged on what you still owe, paying more than the minimum early saves the most. If you carry balances on several cards, focus extra payments on the highest-APR card first while paying at least the minimum on the others, then roll that payment onto the next card once it is cleared.