Credit card interest is the price you pay for borrowing money you haven't paid back yet. It sounds simple, but two design choices — a high APR and daily compounding — turn a modest balance into a debt that follows you for years. Here's exactly how it works, and why the "minimum payment" is the most expensive option on the page.
What APR actually means
APR stands for Annual Percentage Rate — the yearly cost of borrowing on the card, expressed as a percentage. As of recent years, average credit card APRs sit north of 20%. But your card doesn't charge you once a year; it charges you every day. To get the daily periodic rate, the card divides the APR by 365. A 24% APR becomes roughly 0.0657% per day.
Why interest compounds daily
Most issuers use the average daily balance method. Each day, the daily rate is applied to what you owe, and that interest is added to the balance. The next day's interest is calculated on the slightly bigger balance — so you pay interest on your interest. Over a year, daily compounding makes the effective cost noticeably higher than the headline APR suggests.
If you pay your statement balance in full by the due date, most cards charge zero interest on new purchases — that's the grace period. The instant you carry a balance, the grace period collapses and interest starts accruing on purchases from the day you make them.
The minimum payment trap
The minimum payment is usually a tiny slice of your balance — often around 1–3% plus that month's interest. It's designed to keep the account current while keeping you in debt as long as possible. Because most of a minimum payment goes to interest, the principal barely moves.
Consider a $5,000 balance at 24% APR. Paying only a ~2% minimum each month, it can take well over 15 years to clear — and you can end up paying more in interest than the original $5,000. Pay a fixed $250/month instead, and the same debt is gone in about two years for a fraction of the interest. The difference isn't your income; it's whether you attack the principal. That widening gap is exactly what the later rounds of Maxed Out are built to make you feel.
How to pay less interest, faster
- Pay in full whenever you can. Full payment = no interest, full stop.
- Pay more than the minimum. Every extra dollar goes straight to principal and saves future interest.
- Pay early in the cycle. With average-daily-balance billing, lowering the balance sooner lowers the average it's charged on.
- Target the highest APR first (the "avalanche") to cut total interest, or the smallest balance first (the "snowball") for momentum.
- Consider a 0% balance transfer if you qualify — but read the transfer fee and the date the promo rate ends.
The bottom line
Credit card interest isn't a flat fee — it's a daily-compounding meter that runs fastest when you pay the least. The minimum payment keeps the lights on for the lender, not for you. Pay the statement in full if you can; if you can't, pay as far above the minimum as possible and aim every extra dollar at the principal.
Sources & further reading
Related
- ▶ Play Maxed Out — watch the minimum payment trap in fast-forward.
- 📖 Full Maxed Out guide
- 📚 More explainers in the Learn hub