Why paying down a card is different from a loan
A credit card doesn't have a fixed term the way a mortgage or auto loan does — it has a minimum payment, and you decide how much more than that to pay. Interest is charged on the average balance for the billing cycle, compounding month after month for as long as any balance remains. That flexibility is exactly what makes payoff time hard to picture without running the numbers: the same balance can take 3 years or 30, depending only on what you choose to pay each month.
This calculator answers the question either direction: tell it your payment and it tells you the time and total interest, or tell it the time you want and it tells you the payment required.
The math, step by step
Fixed-payment mode walks the balance down month by month:
If payment ≤ interest in month one, the balance can never reach zero — every dollar paid is consumed by interest before it touches the principal, so the calculator reports this explicitly rather than showing a payoff date that will never arrive.
Target-time mode solves the same relationship the other direction, using the standard fixed-payment (annuity) formula — the same one used to price a fixed-rate loan, because "pay this balance off in exactly n months" is mathematically identical whether the debt came from a loan or a card:
A full worked example, with exact numbers
Take a $5,000 balance at 22.99% APR, paying a fixed $200 every month — the defaults already loaded into the calculator above.
Month 1:
| Item | Amount |
|---|---|
| Starting balance | $5,000.00 |
| Interest (balance × 22.99% ÷ 12) | $95.79 |
| Principal (payment − interest) | $104.21 |
| Balance after payment 1 | $4,895.79 |
Over the full payoff: it takes 35 months (2 years, 11 months) and $1,871.08 in total interest — on a $5,000 balance, that's more than a third of the original amount paid again in interest alone.
Enter these same numbers into the calculator above and every figure matches exactly, because it's the same month-by-month calculation running client-side.
What a smaller payment actually costs
On that same $5,000 balance, dropping the payment from $200 to $125 a month doesn't just slow things down a little — it more than doubles the payoff time and the interest paid:
That gap exists because interest is charged on whatever balance remains, and a smaller payment leaves a larger balance outstanding for far longer — the effect compounds the opposite way that extra payments help on an amortizing loan. Turn on "Compare to a different payment" above to see this for your own numbers.
Frequently asked questions
How is the number of months to pay off a credit card calculated?
The calculator starts with your current balance and, every month, charges interest on whatever balance remains (balance times the APR divided by 12), then applies whatever is left of your payment to the principal. It repeats that month by month until the balance reaches zero, counting how many months it took.
Why does the minimum payment take so much longer than a fixed extra payment?
A card's minimum payment is usually calculated as a small percentage of the current balance (commonly 1-3%, though this varies by issuer), so as the balance falls, the required minimum falls too — the payment keeps shrinking right along with the debt, which stretches payoff out for years. A fixed payment that does not shrink attacks the principal much faster.
What happens if my payment doesn't cover the interest?
The balance never goes down — it can even grow, since any interest not covered by the payment gets added back to the balance next month, depending on the issuer's terms. This calculator checks for that case directly and tells you so instead of showing a payoff time that will never happen.
What's the difference between the two modes on this calculator?
"I know my payment" answers: if I pay this amount every month, how long until it's gone and how much interest will I pay? "I know my target payoff time" answers the reverse: if I want it gone in this many months, what does my payment need to be?
Does this calculator account for new purchases I might add to the card?
No — it assumes you stop charging new purchases and only make payments against the existing balance. Adding new spending on top changes the balance the payoff math is running against.
Is APR the same as the interest rate printed on my statement?
For a credit card, yes — enter the APR exactly as your issuer states it. Cards typically charge interest by dividing the APR by 12, which is exactly what this calculator does.
Why is my real card's payoff time a bit different from this calculator's number?
Small differences usually come from average-daily-balance billing, fees added to the balance, or a promotional rate that changes partway through. This calculator uses a straightforward month-end balance and a constant APR.
Can I compare paying more against a lower payment, like the minimum?
Yes — turn on "Compare to a different payment" and enter a second monthly amount. The calculator runs both schedules and shows the interest and time saved by paying the higher amount instead.
Should I pay off a 0% promotional balance the same way?
Enter 0 for the APR and the math still works — with no interest, every dollar of payment reduces the balance directly. Watch for what APR applies after the promotional period ends, since this calculator only models one constant rate.
Can I download the schedule?
Yes — the Download CSV button exports every month (payment, principal, interest, remaining balance) as a CSV file you can open in Excel, Google Sheets, or Numbers.