What Debt Really Costs: APR, Minimums and Fees

The rate printed on a card or a loan offer tells you less than it seems. What a debt actually costs depends on how interest is charged, how long you take to repay, and the fees layered on top. This chapter explains APR, why minimum payments keep balances alive for years, how fees change the true cost of a loan, and what one late payment can do to the rate. Once you can read these numbers, every later decision in this book becomes a comparison you can make yourself.

Interest rate and APR

The interest rate is the price of the money you borrow, charged on the balance you owe. The annual percentage rate (APR) is the yearly cost of credit that the federal Truth in Lending Act requires lenders to disclose in a standard way, so offers can be compared. For an installment loan, APR includes the interest rate plus certain required fees, such as an origination fee, spread over the term. That is why a loan advertised at one rate can show a noticeably higher APR. For a credit card, the APR is the interest rate itself; fees such as annual fees are disclosed separately.

APR also hides how short-term loans add up. A payday loan that charges a fee equal to 15% of the amount borrowed for two weeks sounds modest, but there are 26 two-week periods in a year, so the APR is roughly 390%. When you compare two ways to borrow, compare APRs, and for loans with fees, compare the total you will repay.

Credit cards usually charge interest daily, at the APR divided by 365, on your average daily balance. If you pay the statement balance in full by the due date, most cards charge no interest on purchases at all, thanks to the grace period. Carry any part of the balance and you generally lose the grace period on new purchases too, until the card is paid in full again. The examples in this chapter apply interest monthly, which comes very close to the daily method.

Why minimum payments last so long

A card's minimum payment is set by the issuer, typically a small percentage of the balance plus the month's interest, or a flat floor. It is designed to keep the account current, not to clear it. When most of each payment goes to interest, the balance barely moves.

Federal rules require every card statement to show how long it would take to repay the balance making only minimum payments, and how much you would pay in total. That box is worth reading. The example below shows the same effect with a fixed payment set just above the interest.

At $110 a month, a balance of $5,000 at 22.0% takes 99 months to clear and costs $5,849 in interest, more than the original balance. Adding $90 a month clears it in 34 months, and the interest falls to $1,750. The extra payment saves $4,099.

Real minimums usually shrink as the balance falls, which makes minimum-only repayment slower still than this fixed example. The lesson is the same either way: on revolving debt, the payment you choose, not the payment the lender asks for, sets the cost.

How fees change the cost of a loan

Many personal loans charge an origination fee, often taken out of the money you receive. If you need the full amount, you have to borrow more to cover the fee, and you pay interest on the fee for the life of the loan.

Without a fee, borrowing $10,000 at 12.0% for 3 years means paying $332 a month and $11,957 in total. If a 5% origination fee comes out of the loan, you need to borrow $10,500 to end up with the same cash, and the total repaid rises to $12,555. The advertised rate did not change. The APR on the disclosure would, which is why it is the number to compare.

Other fees to look for before you borrow:

• Balance transfer fees, a percentage of the amount moved to a new card. Chapter 6 shows when they pay for themselves.
• Cash advance fees, usually a percentage of the advance, with interest starting immediately, often at a higher rate than purchases.
• Late fees, capped by federal regulation at amounts that are adjusted for inflation. A 2024 federal rule that would have lowered the cap for large issuers was struck down in court in 2025, so the older limits still apply.
• Prepayment penalties on some loans, which charge you for paying early. Ask before you sign; many lenders do not charge them.
• Annual fees on cards, worth paying only if the card's benefits are worth more to you.

The penalty rate: what one late payment can cost

Most card agreements include a penalty APR, a higher rate that can apply after a late payment. Federal rules limit how it is used: an issuer can apply a penalty rate to your existing balance only after a payment is more than 60 days late, and it must review the account and restore the old rate after six months of on-time payments. For new purchases, it can raise the rate with 45 days' notice. Because a penalty rate can cost far more than the late fee, a missed payment is usually the most expensive mistake a borrower can make.

Paying $200 a month on $5,000 at 22.0% clears the balance in 34 months with $1,750 of interest. If a penalty rate of 30.0% applies to the whole balance, the same payment takes 40 months and the interest rises to $2,943.

One more protection is worth knowing. When a card carries balances at different rates, for example a promotional transfer and regular purchases, federal rules require the issuer to apply any amount you pay above the minimum to the balance with the highest rate first. The minimum itself can go to the lowest-rate balance, so paying only the minimum on such a card keeps the expensive balance in place.