Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Educational information only. This is not a lender quote or personalized financial advice. Your statement and cardholder agreement control the interest calculation on your account.
A credit-card interest estimate starts with three numbers: your balance, APR, and the number of days the balance is carried. A quick monthly estimate is balance × APR ÷ 12, but many issuers calculate interest daily, often from an average daily balance.
Start with the APR on your statement
Cards can apply different APRs to purchases, balance transfers, and cash advances. Use the rate listed beside the specific balance type. A purchase APR is not necessarily the cash-advance APR.
Why a simple calculator can differ from your bill
- Interest may accrue daily, not once a month.
- New transactions and payments change the daily balance.
- A grace period may apply only when the account meets its terms.
- Issuers can apply different methods and minimum interest charges.
A practical estimate
Divide APR by 365 to get a daily-rate estimate. Multiply it by a sample daily balance and the number of days. Treat that number as an illustration, then compare it with your next statement. Paying earlier can reduce interest when it accrues daily.
For a broader repayment view, see our minimum-payment payoff basics. Do not use a generic tool to decide whether to take on new debt.
Sources
Credit Card Interest Cost Estimator
Estimate simple daily interest using your balance, APR, and the number of days carried.
Enter values, then select Estimate interest.
Assumptions and limits
Formula: balance × (APR ÷ 365) × days. This estimate excludes payments, new purchases, fees, compounding, and issuer-specific average-daily-balance methods.
Educational estimate only; your cardholder agreement and statement control.