Credit Card Interest Calculator
Calculate the interest accrued on your credit card unpaid balance based on the balance, APR, and billing cycle day.
※ Use if necessary
Credit Card Interest Calculator
Determine the interest charged on your unpaid credit card balance based on the balance, annual percentage rate (APR), and billing cycle day.
These results are for reference only and were developed for educational and testing purposes. You can also directly access and review the source code, including the logic and free APIs used on this page.
Calculation Results
Date-wise Payment Breakdown
| Date | Daily | Cumulative | Balance | Payoff Total |
|---|
Credit Card Interest Calculator Guide
The Credit Card Interest Calculator estimates the interest charged on an unpaid credit card balance based on the billing cycle day, using the average daily balance method. It highlights savings from early repayment and adjusts calculations based on the actual days in the billing cycle month.
How to Use the Credit Card Interest Calculator
Follow these steps to calculate interest and explore savings:
- Enter the Credit Card Balance: Input the unpaid balance on your credit card.
- Set the Annual Interest Rate (APR): Enter the annual percentage rate provided by your card issuer.
- Specify the Billing Cycle Day: Input the day of the month your billing cycle ends (1–31).
- Calculate: Click "Calculate Interest" to view results in a detailed table.
- Review the Table: The table lists daily interest, cumulative interest, and remaining principal from today to the billing cycle day.
- Check Savings: Below the table, see how much interest you can save by repaying early, including today versus the billing cycle day.
Understanding Credit Card Interest
Credit card interest is calculated using the average daily balance method, applying the daily periodic rate to the balance over the billing cycle.
Average Daily Balance Method
This method calculates interest based on the daily balance.
- Formula: Interest = Average Daily Balance × Daily Periodic Rate × Number of Days
- Daily Periodic Rate = APR / 365
- Interest accrues only on unpaid balances after the grace period.
Grace Period
Most credit cards offer a grace period where no interest is charged if the balance is paid in full by the due date.
- Typically 21–25 days from the end of the billing cycle.
- Not applicable if a balance is carried over.
Early Repayment Savings
Repaying your balance before the billing cycle day reduces interest by limiting the days it accrues.
- Paying one day early saves one day’s interest.
- Paying today can significantly reduce interest compared to waiting until the cycle’s end.
- If today’s date exceeds the billing cycle day, calculations extend to the next month’s billing day.
Factors Affecting Credit Card Interest
Several factors influence interest charges:
Annual Percentage Rate (APR)
The yearly interest rate applied to unpaid balances.
- Higher APRs increase interest costs.
- APRs vary by card type and creditworthiness.
Unpaid Balance
The amount unpaid after the due date determines the interest base.
- Larger balances lead to higher interest.
- Payments reduce the interest-bearing balance.
Billing Cycle Duration
The number of days in the cycle’s month affects total interest.
- Longer cycles (e.g., 31 days) increase interest for carried balances.
- Typically 28–31 days, based on the calendar month.
- If today’s date exceeds the billing cycle day, the calculator extends to the next billing day.
Common Credit Card APRs
APRs vary by card type and market conditions:
Standard Credit Cards
- 15%–25% (based on credit score).
Rewards Credit Cards
- 18%–28% (higher due to rewards).
Introductory APR Cards
- 0% for 6–18 months, then 15%–25%.
Final Tips for Using the Calculator
- Use the exact APR and balance from your credit card statement.
- Verify the billing cycle day with your card issuer.
- The calculator assumes a constant balance; actual interest may vary with transactions.
- Review savings information to see the benefits of early repayment.
- If today’s date exceeds the billing cycle day, calculations extend to the next billing day to help plan repayments.
- Consult your credit card agreement for precise terms.
Results are estimates and may differ due to fees, payment timing, or compounding methods.