Credit Card Interest Calculator

This credit card interest calculator shows you exactly how credit card interest works — how your APR turns into a daily rate, how daily compounding silently grows your balance, and how long it will take to pay off what you owe at your current payment level. Most cardholders know their APR but have no idea how much interest they're actually paying each month or how many years minimum payments will trap them in debt.

Enter your balance, APR, and monthly payment. The calculator instantly shows your monthly interest charge (under both daily and monthly compounding), your payoff timeline, and the total interest you'll pay over the life of the balance. If your payment barely exceeds the interest, you'll see a warning — along with the minimum payment needed to actually make progress.

The average APR on credit card accounts that paid interest was 22.32% in 2025, according to the Federal Reserve's G.19 Consumer Credit release of September 8, 2026. At that rate, a $5,000 balance with a $150/month payment takes over four years to pay off and costs more than $2,000 in interest alone.

Nearly all US credit cards use daily compounding — a fact buried in the fine print that makes a meaningful difference compared to simple monthly interest. Here's the exact method, as described by the Consumer Financial Protection Bureau (CFPB):

Worked example — $5,000 at 24.99% APR:

• DPR = 24.99% ÷ 365 = 0.0685% per day
• Monthly interest (daily compounding): $5,000 × ((1.000685)^30 − 1) = $103.71
• Monthly interest (simple monthly): $5,000 × (24.99% ÷ 12) = $104.13

The difference between daily and monthly compounding on a single month is small, but over years of revolving balances it compounds into hundreds of extra dollars. This calculator shows both methods side by side so you can see the real-world impact.

Under Federal Reserve Regulation Z (Truth in Lending), card issuers must disclose both the APR and the daily periodic rate on every statement. Look for your DPR in the interest charge section of your statement — this calculator uses the same math your issuer does.

Credit card minimum payments are typically calculated as the greater of a flat floor ($25–$35) or 1–2% of the balance. On a $5,000 balance at 25% APR, the minimum might be $100 — but $104 of that is interest. You're paying down only a few dollars of principal per month, which is why the CFPB warns that minimum payments can stretch payoff to 15–25 years.

Try this experiment in the calculator above: enter your balance and APR, then set the payment to your current minimum. Note the payoff time and total interest. Now double the payment. In most cases, doubling cuts the payoff time by 70–80% and the interest by even more — that's the power of escaping the minimum payment trap.

Every dollar above the interest charge goes straight to principal. The more principal you eliminate today, the less interest accrues tomorrow, creating a virtuous cycle that accelerates over time. This is the same compounding math that works against you when you carry a balance — turned around to work for you when you pay extra.

If you're carrying balances on multiple cards, use our Debt Payoff Optimizer to compare snowball vs avalanche strategies. For a single card, this calculator gives you the fastest answer.

From highest to lowest impact:

1. Pay the full statement balance each month. If you pay in full by the due date, you owe zero interest — the grace period (typically 21–25 days per the CFPB grace period guide) means no interest accrues on purchases.
2. Transfer to a 0% APR balance transfer card. Many cards offer 12–21 months at 0% with a 3–5% transfer fee. On $5,000, a 3% fee ($150) saves over $1,000 in interest if you pay it off during the promo period.
3. Consolidate with a personal loan. Fixed-rate personal loans at 8–15% APR can dramatically undercut credit card rates. Use our Complete Loan Calculator to model the monthly payment.
4. Call and ask for a rate reduction. Issuers sometimes lower rates for loyal, on-time customers — a 5-minute call can save hundreds.
5. Pay more than the minimum. Even $50 extra per month compresses your payoff timeline significantly. Use this calculator to see exactly how much.

For credit cards, APR and interest rate are effectively the same thing — unlike mortgages and auto loans, where APR folds in origination fees, points, and closing costs. Your credit card APR is the interest rate applied to your balance. Some cards have multiple APRs: one for purchases, a higher one for cash advances (typically 25–30%), and a penalty APR (up to 29.99%) that triggers if you pay late.

This calculator uses your purchase APR by default. If you've taken a cash advance, enter that separate (usually higher) APR to see the true cost — cash advances also have no grace period, meaning interest starts accruing immediately with no free float.

For context on where rates are headed: the Federal Reserve publishes aggregate credit card interest rate data in the G.19 Statistical Release, updated monthly. When the Fed raises or cuts rates, most variable-rate cards adjust within 1–2 billing cycles.