Credit Card Calculator
Find out how many months it takes to pay off a credit card balance at a fixed monthly payment, and how much interest you'll pay.
How It's Calculated
Formula
n = \frac{-\ln\left(1 - \dfrac{r B}{P}\right)}{\ln(1+r)} \qquad r = \frac{\text{APR}}{12}This calculator finds how many months it takes to pay off a credit card balance at a fixed monthly payment, using the standard closed-form payoff-period formula for a balance accruing interest at a fixed monthly rate. Interest accrues each month on the remaining balance, and your fixed payment covers that interest plus a shrinking share of principal, the same way a standard loan amortizes — except here you enter the payment and the calculator solves for how long it takes, rather than the other way around. If your payment doesn't exceed the first month's interest, the balance would never shrink, and that's reported explicitly rather than as an infinite or negative payoff time.
Worked Examples
$5,000 balance, 22.99% APR, $200/month payment
- Monthly periodic rate: 22.99% / 12 ≈ 1.916%
- First month's interest: 5,000 × 1.916% ≈ $95.79 (well under the $200 payment, so it will amortize)
- Solving the payoff formula: n ≈ 35 months
- Total interest paid over 35 months: ≈ $1,871
Payment too small: $10,000 balance, 24% APR, $50/month
- First month's interest: 10,000 × (24%/12) = $200
- The $50 payment doesn't even cover the $200 monthly interest, so the balance would never be paid off at this payment amount
Frequently Asked Questions
How is this different from the Credit Cards Payoff Calculator?
This calculator handles one card at a fixed monthly payment. The Credit Cards Payoff Calculator handles multiple cards at once and compares debt snowball vs. debt avalanche payoff strategies across all of them.
Does this use my card's minimum payment?
No. You enter the exact fixed monthly payment you plan to make; this calculator doesn't assume or compute a minimum-payment formula or any specific issuer's or regulator's minimum-payment rules.
What happens if my payment doesn't cover the interest?
If your monthly payment is less than or equal to the first month's interest charge, the balance would grow or stay flat forever instead of shrinking — this calculator reports that directly instead of showing an infinite or misleading payoff time.
Does this account for new purchases or a variable APR?
No. This is a static payoff projection assuming no new charges are added to the balance and the APR stays fixed for the entire payoff period.