Credit Card Interest Calculator
See the interest your credit card charges this month and per day, then compare a fixed payment, minimum payments or a payoff goal, with intro APR, new charges and a month-by-month schedule.
How it works
Monthly interest = balance × (APR ÷ 12) · Daily interest = balance × (APR ÷ 365) · Daily compounding: monthly rate = (1 + APR ÷ 365)^(365 ÷ 12) − 1 · Payment for n months = B × r ÷ (1 − (1 + r)^−n) · Minimum payment = interest + % of balance (or % of balance), never below the floor
Card interest comes from the APR split into a small periodic rate. The simple version is APR ÷ 12 per month; most issuers actually use a daily rate of APR ÷ 365 on the average daily balance and add the interest every day, which you can pick under "Interest method". Each month the calculator charges interest on the balance, adds any new charges, subtracts your payment and repeats until the balance reaches zero. You can pay a fixed amount, pay only the minimum (interest plus a percent of the balance, or a flat percent, with a dollar floor), or set a payoff goal in months and get the payment that meets it. An intro APR applies for the months you enter and then the regular APR takes over. The comparison table runs the same card through minimum payments, your plan and 12-, 24-, 36- and 60-month goals, so you can see what each choice costs in time and interest.
Worked example
A $4,000 balance at 24% APR accrues 4,000 × (24% ÷ 12) = $80 of interest this month, about $2.63 a day, or $78.90 over a 30-day billing cycle. Paying $150 a month clears it in 39 payments (3 years 3 months), the last one $73.39, with $1,773.39 of interest. Paying only the minimum (interest + 1%, at least $25) starts at $120.80 and takes 209 months (17 years 5 months) with $6,762.50 of interest. To be debt-free in 24 months instead, you would pay $211.48 a month and $1,075.63 of interest.
Sources: CFPB — How does my credit card company calculate the amount of interest I owe? · CFPB — Regulation Z, Appendix M1: repayment disclosures (minimum payment estimates)
Frequently asked questions
Is credit card interest daily or monthly?
Most issuers use a daily periodic rate (APR ÷ 365) on your average daily balance and add the interest to your monthly statement. Choose "Daily compounding" under More options to model that. APR ÷ 12 is a close, easy-to-check approximation and gives almost the same answer.
How is the minimum payment calculated?
It depends on the card agreement. Many US cards charge the interest for the month plus 1% of the balance, with a floor of about $25–$40; others ask for 2%–3% of the balance. Pick the rule and percent that match your statement. Because the minimum falls as the balance falls, paying only the minimum can take many years.
How much do I need to pay to be debt-free by a date?
Choose "Payoff goal" and enter the number of months. The calculator finds the fixed monthly payment that clears the balance on time, including any intro APR and new charges you enter, and shows the total interest.
How do I avoid interest entirely?
Pay the full statement balance by the due date every month. Purchases then stay inside the grace period and are never charged interest. Once you carry a balance, new purchases usually start collecting interest right away, which is how the new-charges option works here.
How does a 0% intro APR change the result?
Enter the intro APR and how many months it lasts. During those months your whole payment goes to the balance, so payoff is faster and cheaper. The regular APR applies to whatever is left when the promotion ends.
Does a cash advance work the same way?
No. Cash advances usually carry a higher APR, collect interest from the day you take them with no grace period, and add an upfront fee. Run a cash-advance balance separately with its own APR.
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Educational estimate, not financial advice. Actual loan terms, fees and interest depend on your lender and credit profile.