Credit Card Interest Calculator
See how long it takes to pay off your balance — and how much interest you will really pay.
The Credit Card Interest Calculator shows the real cost of carrying a balance. Enter what you owe, your card's APR and the monthly payment you can afford, and the tool simulates your payoff month by month: how long it will take, how much interest you will pay in total, and roughly when the card will finally be at zero.
The math behind credit cards is harsh: interest is charged on your balance every month at roughly APR ÷ 12, so early payments go mostly to interest, not your debt. The tool makes this visible with a yearly milestone table of your shrinking balance — and it warns you clearly if your payment is so small that it does not even cover the monthly interest, in which case the debt would grow forever and never be paid off.
You can use it to test 'what if' scenarios: what happens if I double my payment, or transfer to a 0% balance card, or pay just the minimum? The answers are often surprising and motivating. The simulation runs locally in your browser and assumes a fixed APR with no new purchases or fees.
Months to pay off
36
≈ 3 years
Total interest paid
$2,135.16
Estimated payoff date
Sep 2029
Paying $200.00 every month
Balance over time (yearly milestones)
| Month | Year | Remaining balance |
|---|---|---|
| 12 | 1 | $3,708.13 |
| 24 | 2 | $2,053.76 |
| 36 | 3 | $0.00 |
How to use the Credit Card Interest Calculator
- Enter your current credit card balance.
- Type your card's annual percentage rate (APR) — it is on your statement.
- Enter the fixed monthly payment you plan to make.
- Read your months to payoff, total interest and estimated payoff date.
- Try increasing the payment to see how much interest you can save.
Frequently asked questions
How is credit card interest calculated monthly?
Cards charge interest on the average daily balance at a daily rate (APR ÷ 365). This calculator approximates that with monthly compounding at APR ÷ 12 per month, which is very close for typical balances. Interest is added before your payment is applied, just like a real card.
What happens if my payment doesn't cover the monthly interest?
Your balance grows every month even though you are paying — the debt never shrinks. The calculator detects this and shows a warning instead of a payoff date. If that happens, increase your payment above the monthly interest figure shown, or look into a balance transfer.
Why do I save so much interest by paying more each month?
Every extra dollar you pay goes straight to principal, so it stops accruing interest immediately — and it stays paid off forever. That makes extra principal payments dramatically more valuable than they look: paying $250 instead of $200 a month on a $5,000 balance at 25% APR can save thousands of dollars and years of payments.
What about minimum payments?
Minimum payments are typically 1–3% of the balance plus interest, which mostly covers interest in the early years. If you only pay the minimum, payoff can stretch to decades with total interest exceeding the original debt. Try the 'snowball' approach: pay the minimum on all cards and throw every extra dollar at the highest-APR card first.
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