Credit Card Interest Calculator
Estimate how long a fixed monthly payment could take to clear a credit card balance and how much interest you could pay. Start with the balance and APR on your statement, then choose a payment you can sustain without adding new debt.
Paying $50 more each month could save about 5 months and $306.04.
Monthly approximation; no new spending or fees. Your issuer may use daily balances.
What to enter
Keep balances with different rates separate unless you are deliberately using a simplified blended estimate. Cash advances, deferred-interest plans, issuer minimum-payment formulas, and daily transaction timing need additional information this model does not include.
| Input | Use this value |
|---|---|
| Balance | The amount you want to repay |
| APR | The annual rate for that balance, entered as a percentage |
| Monthly payment | A fixed amount you plan to pay each month |
| Promotional months remaining, if applicable | The number of full modeled payment periods left at the promotional rate |
| Promotional APR, if applicable | The rate during those periods |
What the estimate shows
You receive a modeled payoff time, total interest, total payments, and a period-by-period balance. A final payment may be smaller than the regular payment. If the payment cannot reduce the balance once the regular rate applies, the calculator identifies that problem instead of presenting a payoff date.
A result beyond the modeled limit is also reported as incomplete. It must not be interpreted as a paid-off balance or zero borrowing cost.
What another $50 a month can change
For a hypothetical $5,000 balance at 24% APR, with no new spending or fees:
Moving from $200 to $250 saves an estimated $551.20 and ten months. The calculation assumes the larger payment is maintained throughout; it is not a promise of savings if spending or interest rates change.
| Fixed payment | Payoff time | Total interest | Total paid |
|---|---|---|---|
| $200 | 36 months | $2,000.57 | $7,000.57 |
| $250 | 26 months | $1,449.37 | $6,449.37 |
| $300 | 21 months | $1,143.33 | $6,143.33 |
How the model works
For each monthly period, the model multiplies the opening balance by APR/12, rounds that interest to cents, and subtracts the payment from the balance plus interest. During a promotional period, it uses the promotional rate instead. The regular rate starts in the next modeled period.
Real card agreements can use daily balances and different billing-cycle lengths. Payment timing and multiple rate categories can therefore produce different charges. CFPB interest calculation guide
For purchase balances that qualify for a grace period, you may avoid interest by meeting the card's full-payment conditions. Do not use an interest-bearing projection to infer that interest necessarily applies to every purchase. CFPB grace-period guide
Test the plan before relying on it
Run the payment you expect to make, then a smaller payment that might be necessary in a difficult month. If the difference makes the schedule unrealistic, reconsider the borrowing amount or timeline.
For several debts, use the debt payoff calculator. For the meaning of your rate, read what credit card APR means.