BCBetter Calculators

Credit Card Interest Calculator

See exactly how much interest you'll pay and how long it will take to pay off your credit card balance.

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Enter your values and click Calculate

How It Works

Monthly interest rate = APR ÷ 12 ÷ 100. Each month: interest charge = remaining balance × monthly rate. New balance = old balance + interest charge − monthly payment. This repeats until the balance reaches zero. The calculator iterates month by month rather than using a closed-form formula, which correctly handles the final partial payment. A warning is shown if the monthly payment does not exceed the first month's interest charge — in that case the balance grows indefinitely rather than being paid off. Total interest = sum of all monthly interest charges. Interest as a percentage of original balance = total interest ÷ original balance × 100.

Examples

Minimum Payment Trap
$5,000 balance at 24.99% APR, paying minimum $100/month.
Result: Takes approximately 109 months (9 years), total interest ~$5,800 — more than the original balance.
Aggressive Payoff
$5,000 balance at 24.99% APR, paying $300/month.
Result: Paid off in approximately 20 months, total interest ~$1,300.
Low APR Balance Transfer
$8,000 balance at 5.99% APR (post-transfer), paying $250/month.
Result: Paid off in approximately 35 months, total interest ~$697 — a fraction of what high-APR cards charge.

Frequently Asked Questions

How is credit card interest calculated?
Credit card interest is calculated using your Average Daily Balance (ADB) method in most cases — the average balance across all days in the billing cycle is multiplied by the daily periodic rate (APR ÷ 365) and then by the number of days in the cycle. This calculator uses a simplified monthly rate (APR ÷ 12) applied to the beginning balance each month, which gives a very close approximation of actual interest charges. The exact amount will vary slightly based on your card's specific calculation method and when you make payments.
What is a good APR for a credit card?
The average credit card APR in the US was approximately 21–22% in 2026. A 'good' APR depends on your credit profile: excellent credit (750+) typically qualifies for 15–18% APR; good credit (700–749) qualifies for 18–22%; fair credit pays 22–27%+; poor credit may face 27–36% or be limited to secured cards. Rewards cards often carry higher APRs. If you carry a balance, APR is one of the most important factors in card selection — if you pay in full monthly, the APR is irrelevant since you pay no interest.
Should I pay more than the minimum payment?
Almost always yes — the difference is dramatic. On a $5,000 balance at 24.99% APR, paying $100/month (roughly minimum) takes 9 years and costs $5,800 in interest. Paying $300/month takes 20 months and costs $1,300 in interest — saving $4,500 and 7 years. Even adding $50/month to minimum payments dramatically accelerates payoff. The credit card minimum payment is designed by card issuers to maximize long-term interest income — it is not designed to help you become debt-free quickly.
Is a balance transfer worth it?
A 0% introductory APR balance transfer can save significant money if you pay off the balance before the promotional period ends (typically 12–21 months). Balance transfer fees are usually 3–5% of the transferred amount — compare this to the interest you'd pay staying on the original card. For example, transferring $5,000 with a 3% fee costs $150 upfront but saves you $1,000–$2,000+ in interest if you pay it off during the promo period. Avoid making new purchases on a balance transfer card — new purchases often accrue interest immediately at the regular APR.