Paying a card balance down
Card interest is charged on the balance you still owe. A payment that only covers interest never reduces the debt. Keep the balance and the rate the same and change only the payment. The change in months and in interest is the effect of the fixed payment. Leave new purchases out of that balance. The sample amounts on the page are not a quote from a bank, a card issuer, or an employer. Replace them with the figures on your statement and run the page twice to see which field moves the result.
Minimum is not a plan
A minimum often shrinks as the balance shrinks, so the payoff date keeps moving.
The calculator asks for one payment you choose. That is the number to compare.
A 3,000 balance at 18% with a fixed 150 payment reduces principal after that month's interest. A minimum that shrinks with the balance keeps pushing the end date back. This page uses the fixed payment you choose, not the issuer's minimum.
The rate is monthly
A 18% APR on this page is 1.5% of that month's balance, not 18% of the original balance every month.
If the payment is smaller than that month's interest, the balance grows and the page says so.
18% a year is 1.5% of that month's balance. On 3,000 the interest is about 45. A payment below that interest makes the balance grow, and the page says so. It is not 18% of the original charge every month.
New spending
The page assumes you stop adding purchases. A new charge starts the clock again.
Pay the new spending in full, then keep the fixed payment on the old balance.
The page assumes no new purchases. If you spend another 200 this month, pay that amount separately and keep the fixed payment on the old balance. Folding new spending into the same plan moves the end date out again.
Related tools
These figures are estimates you can recompute from the formula on the page. They are not a lender quote, a tax bill, a payroll statement, or financial advice.