Online Tool Store
Credit Card Interest Calculator
Estimate credit card interest, payoff time, and total repayment from your balance, APR, and monthly payment with a clear local breakdown.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Payoff scenario
Card balance details
Estimated payoff
3 years 9 months
First month interest
$104.13
Total interest
$2,712.90
Total repaid
$7,712.90
Interest share
First months
Illustrative schedule| Month | Payment | Interest | Balance |
|---|
Estimate only. Issuers may use daily balances, fees, changing rates, and different payment allocation rules.
How it works
- Enter the outstanding card balance and advertised annual APR.
- Add the amount you plan to pay each month and any continuing monthly purchases.
- Review the estimated payoff time, interest cost, total repaid, and opening schedule.
- Try a larger payment to see how much time and interest it could save.
The payoff calculation
monthly rate = APR / 12
next balance = current balance + (current balance x monthly rate) + new spending - payment
The calculation repeats month by month, using the final smaller payment when the remaining balance is below the regular payment. It assumes a constant APR and fixed payment; actual issuers commonly accrue interest daily, so this is best used for planning and comparison rather than statement reconciliation.
FAQ
How is credit card interest estimated?
The calculator divides the annual percentage rate by 12 to estimate a monthly rate, applies it to the outstanding balance, adds optional new spending, and then subtracts the payment. This repeats until the estimated balance reaches zero.
Why might my statement interest be different?
Many card issuers calculate interest from an average daily balance and a daily periodic rate. Statement dates, compounding, fees, cash advances, promotional rates, and payment allocation rules can all change the real result.
What happens if my payment is too low?
If the payment does not cover the estimated interest plus new spending, the balance will not decrease. The calculator flags that situation instead of showing a misleading payoff date.
Does making new purchases affect payoff time?
Yes. Recurring new spending raises the balance every month before the payment is applied. Even modest spending can extend payoff time substantially when the APR is high.
Is this financial advice or an issuer quote?
No. It is an educational estimate based on constant inputs. Use your card agreement and statements for exact figures, and contact the issuer or a qualified adviser for decisions about debt.
Can I model a 0% promotional APR period?
You can enter 0 for APR to see what a promo period alone would look like, but the calculator assumes a constant rate throughout, so switch the APR to the card's ongoing rate to see the payoff after the promo ends.
How we compare
| Feature | Online Tool Store | Issuer payoff estimate | Spreadsheet |
|---|---|---|---|
| Instant what-if payment changes | Yes | Sometimes | After setup |
| New monthly spending scenario | Included | Varies | Custom formula |
| First-month schedule preview | Included | Statement specific | Must be built |
| Exact fees and daily balance method | Estimate only | Most accurate | Only if modeled |
Use this calculator for quick payoff planning and payment comparisons. Your issuer's statement or payoff quote remains the authoritative source for exact interest, fees, and due dates.