How this calculator works
Counts the months until the balance hits zero at a fixed monthly payment, charging interest monthly at APR ÷ 12. Add $50 to the payment and watch the interest line drop — that is the whole trick with card debt.
- Monthly interest rate = APR ÷ 12 ÷ 100.
- Months to pay off = −ln(1 − rate × balance ÷ payment) ÷ ln(1 + rate), rounded up to a whole month.
- Total interest is found by running the balance forward month by month: add that month's interest, subtract the payment, repeat until it hits zero.
Worked example
With these inputs: card balance $2,500; apr 24.99%; monthly payment $150.
The result is paid off in 1 year 9 months, with total interest $602.83 and total paid $3,102.83. An extra $50 a month saves $176.48 in interest and 6 months.
Example: paying off $5,000 at 22.99% APR
The same card balance with five different fixed monthly payments. Interest is charged monthly (APR ÷ 12) and no new purchases are added.
| Monthly payment | Time to pay off | Total interest | Total paid |
|---|---|---|---|
| $125 | 6 years 5 months | $4,577 | $9,577 |
| $150 | 4 years 6 months | $3,045 | $8,045 |
| $200 | 2 years 11 months | $1,871 | $6,871 |
| $300 | 1 year 9 months | $1,081 | $6,081 |
| $500 | 1 year | $604 | $5,604 |
Doubling the payment from $150 to $300 a month clears the card in 1 year 9 months instead of 4 years 6 months and saves $1,964 in interest.
Why the minimum payment takes so long
Card issuers usually set the minimum payment at a small percentage of the balance plus interest. As the balance falls, so does the minimum, so the payoff date keeps moving further away. A fixed payment — even one only a little higher than today's minimum — breaks that cycle, because every dollar above the month's interest goes straight to the balance.
That's why this calculator asks for a fixed monthly payment rather than a minimum-payment percentage. Decide what you can pay every month and keep paying it, even after the statement minimum drops.
Three ways to use the result
Pick a target date and work backwards: raise the payment until the months line reads the date you want.
Compare a balance transfer. Put in the balance plus the transfer fee, and the promo APR, to see whether you'd clear the card before the promo ends.
Once you know the payment, add it as a monthly bill so it shows up with your rent and utilities and never gets skipped. The button under the result does that in Bill Organizer.
Wondering whether extra money should go on the card or into investments instead? The invest or pay off debt calculator runs both plans with the same monthly money.
To check this month's interest charge against your statement, the credit card interest calculator uses the daily periodic rate and average daily balance. Paying cards down also lowers your credit utilization, one of the biggest factors in a credit score.
Frequently asked questions
How long will it take to pay off my credit card?
Divide the problem into interest and principal: each month the card charges APR ÷ 12 on the balance, and only the part of your payment above that interest reduces the debt. The calculator runs that month by month. With the default example — $2,500 at 24.99% paying $150 a month — it takes 21 months.
What happens if I only pay the minimum?
The minimum usually shrinks as the balance shrinks, so payoff can stretch out for many years and the interest can end up larger than the original purchase. Paying a fixed amount above the minimum is the simplest fix.
Does paying twice a month help?
Slightly. Card interest is typically calculated on your average daily balance, so paying part of the amount earlier in the cycle lowers that average. The bigger effect still comes from the total you pay each month, which is what this calculator models.
Should I pay off the highest-interest card first?
If you have more than one card, paying the highest APR first (the avalanche method) costs the least interest. Paying the smallest balance first (the snowball method) clears a card sooner. The Debt Snowball & Avalanche Calculator compares both for up to three debts.
Is this calculator accurate for my card?
It uses standard monthly compounding at a fixed APR and a fixed payment. Real statements can differ by a few dollars because of daily balance calculations, new purchases, fees or a changing APR. Stop using the card while you pay it down and the estimate will be close.