A credit card is revolving debt that charges compound interest on your unpaid balance — typically 18–24% APR in 2026. This calculator shows your exact payoff timeline, total interest paid, and how extra payments accelerate debt elimination. It uses the same daily compounding method your card issuer uses to calculate your monthly statement balance.
Credit Card Interest Calculator
Calculate interest charges, payoff timeline, and total debt. Model different payment strategies to become debt-free faster.
How Credit Card Interest Is Calculated
Credit card issuers use daily compounding to calculate interest. Your daily balance is multiplied by your daily periodic rate (annual APR ÷ 365), then summed across all days in the billing cycle. This "average daily balance" method is the most common and charges interest on purchases from the transaction date forward.
| Variable | Definition |
|---|---|
| Interest | Monthly interest charge added to your balance |
| Daily Balance | Average balance across all days in the billing cycle |
| Daily Rate | Annual APR ÷ 365 (e.g., 20% APR = 0.0548% daily) |
| Days | Number of days in the billing cycle (typically 28–31) |
Example: A $5,000 balance at 20% APR in a 30-day cycle incurs ~$82 in interest. If you pay $500 midway through the cycle, your daily balance drops and interest charge is lower (~$72). This calculator tracks daily balances and compounds daily interest to show your exact payoff timeline.
⚠️ Expert Pro-Tip
Minimum Payments Are a Trap — The Math That Keeps You Broke: Paying just the minimum (typically 2–3% of balance) on a $10,000 credit card balance at 20% APR takes 5+ years to pay off and costs $6,000 in interest — you're paying 60% more than you borrowed. Banks design minimum payments to keep you paying interest forever. The move: Pay at least 5–10% of your balance (or $200/month, whichever is higher) every month. On that same $10,000, you'll be debt-free in 18 months for ~$1,500 in interest. The difference is paid freedom vs. financial servitude.
Credit Card Interest FAQ
What's the average credit card APR in 2026?
The average credit card APR in April 2026 is 19.2% for new cardholders. Premium rewards cards average 21–24%, while 0% intro APR offers last 6–21 months for balance transfers or new purchases. Credit score matters: a 750+ score qualifies for 15–18% rates, while a 600 score faces 24–27%. The median American carries $6,500 in credit card debt at ~20% APR, paying ~$1,300 annually in interest alone.
Should I do a balance transfer or personal loan?
Balance transfer cards offer 0% APR for 6–21 months but charge 3–5% upfront fee and have high post-promo rates (24–26%). Personal loans have fixed rates (10–28% depending on credit) but no transfer fees. On $10,000 at 20% APR: A balance transfer card saves you to $1,500 if you pay off before the 0% expires. A personal loan at 12% APR costs only $600 in interest annually — better long-term, but higher credit requirements. Use balance transfers to buy time; use personal loans if you plan to carry debt 2+ years.
What's the difference between avalanche and snowball methods?
Snowball: Pay minimum on all debts, attack the smallest balance first. Psychology win — fast wins build momentum. Avalanche: Attack highest APR first (credit cards at 20% before personal loans at 8%). Math wins — saves thousands in interest. On $20,000 in debt ($10,000 credit card at 20% + $10,000 personal loan at 8%), snowball might take 4 years, avalanche 3 years with $2,000 less interest paid. Most people succeed with snowball's momentum but regret it years later. Best move: start with snowball for 3 months to build confidence, then switch to avalanche.
How much interest will I pay if I only make minimum payments?
On a $5,000 balance at 20% APR paying minimum (2.5% monthly): You'll pay $4,000 in interest over 6.5 years, nearly doubling your original debt. At $200/month (4% of balance): You'll pay $1,000 in interest over 26 months — 1/4 the interest and 5x faster. This calculator shows the exact timeline and total interest for your minimum payment amount — run it, see the number, and decide if that's acceptable.
What if I miss a payment or pay late?
Late fees are $25–40 per occurrence, and your APR can jump to a "penalty APR" (often 29.99% — the legal maximum). Missing one payment triggers a 30-day late mark on your credit (680 point hit), and after 60 days, most cards raise your rate to penalty APR permanently. Most penalty APRs can't be removed even if you resume on-time payments. Solution: Set up autopay for at least the minimum. If you do miss, call the issuer before 30 days — many will waive one late fee and won't activate penalty APR if you ask.
Is carrying a small balance to "build credit" a good idea?
No. Carrying a $500 balance at 20% APR costs $100/year in interest to "build credit" — a bad trade. Myth: You need debt to build credit. Truth: You build credit by using cards and paying on time with zero balance. Charge something small (gas, groceries), pay it off in full monthly. Your credit score improves in 6 months with $0 interest paid. Carrying debt is expensive, not heroic.