How Credit Card Interest Works, and How to Pay Less

Credit card interest is charged on the balance you carry from one month to the next. Most issuers work it out daily: they take your APR, divide it by 365 (or 360), and apply that daily rate to your average balance over the billing cycle, according to the CFPB.

If you pay your full statement balance by the due date every month, you usually pay no interest on purchases at all. The rest of this guide is about what happens when you don't: what a balance really costs, and the moves that bring that cost down.

How is credit card interest calculated?

Three numbers decide it:

• Your APR, the yearly interest rate. The Federal Reserve's latest figure puts the average at 22.36% for cards that were charged interest (August 2026, released October 7).
• The daily periodic rate: your APR divided by 365 or 360, depending on the issuer. At 22.36%, that's about 0.0613% a day. The CFPB explains the daily periodic rate.
• Your average daily balance: the issuer adds up your balance at the end of each day in the billing cycle, after purchases and payments, and divides by the number of days.

Interest for the month is roughly the average daily balance × the daily rate × the number of days in the cycle. Your card agreement says exactly which method your issuer uses, and some add each day's interest to the balance, so you pay interest on interest.

What a $3,000 balance costs

Say you carry $3,000 on a card at 22.36% and don't add anything to it:

• Each day: about $1.84 in interest.
• A 30-day billing cycle: about $55.13.
• A year at that balance: about $671, before any compounding.

Pay it down to $2,000 and the month's interest drops to about $36.76. That's $18 a month you keep, every month the balance stays lower.

How fast you pay makes the biggest difference. At the same 22.36%, with no new charges:

• $100 a month: paid off in about 45 months, with about $1,435 in interest.
• $150 a month: about 26 months and $789.
• $200 a month: about 18 months and $552.
• $300 a month: about 12 months and $351.

Going from $100 to $200 a month saves about $880 and two years. Plug in your own balance, rate and payment with our Debt Payoff Calculator.

How the grace period saves you money

The grace period is the time between the end of your billing cycle and your payment due date. If you pay the statement balance in full by the due date, you're usually charged no interest on the purchases on that statement. Issuers have to mail or deliver your statement at least 21 days before the payment is due.

Here's the catch: carry any balance past the due date, and you lose the grace period. New purchases then start collecting interest from the day you make them. Getting it back usually means paying the full balance on time for one or two billing cycles in a row; your card agreement says how many.

That's why paying "almost all" of the balance costs more than it looks. Leave $100 unpaid on a $2,000 statement and you can be charged interest on new purchases too, not just on the $100.

Why your card might have more than one interest rate

• Purchases have the standard APR.
• Cash advances usually have a higher APR, plus a fee, and no grace period: interest starts the day you take the cash.
• Balance transfers may have a 0% introductory rate, usually with a transfer fee of a few percent.
• A penalty APR can apply after a late payment. Federal rules say the issuer can't raise the rate on your existing balance unless your minimum payment is more than 60 days late, but it can apply a higher rate to new purchases after giving you notice.

When you pay more than the minimum, the extra has to go to the balance with the highest APR first. The minimum itself can go to the lowest-rate balance.

Are credit card interest rates variable?

Most are. A variable APR moves with an index, usually the prime rate, plus a margin set by the issuer. When the Federal Reserve raises or cuts rates, the prime rate follows, and your card's APR changes with it a billing cycle or two later. Your margin depends mostly on your credit when you open the card, which is why two people can get very different rates on the same card.

How to pay less credit card interest

1. Pay the full statement balance by the due date, if you can. It's the only way to pay no interest at all.
2. Pay more than the minimum. The box on your statement shows how long the minimum payment would take, and the figures above show how much a bigger payment saves.
3. Pay early in the cycle. Interest runs on your average daily balance, so a payment made mid-cycle lowers it for more days than one made on the due date. It also lowers the balance that gets reported, which helps your credit utilization.
4. Ask for a lower rate. Call the number on the back of your card. If you've paid on time for a year or more, it's worth asking, and the worst answer is no.
5. Move the balance to a 0% card. A balance transfer card can stop the interest for 12 to 21 months, after a fee. Our page on the best balance transfer credit cards compares the intro periods and fees.
6. Consolidate at a lower rate. A personal loan with a fixed rate below your card's APR turns the balance into one payment with an end date, if your credit qualifies you for a better rate.
7. Stop adding to the balance while you pay it down. Use a debit card for a while if that helps.

If you're carrying balances on several cards, our guide to getting out of credit card debt walks through which to pay first.

Sources

• How does my credit card company calculate the amount of interest I owe?, CFPB
• What is a "daily periodic rate" on a credit card?, CFPB
• Consumer Credit, G.19, Federal Reserve (released October 7, 2026: 22.36% on accounts assessed interest, August 2026, preliminary)
• 12 CFR 1026.5, CFPB (Regulation Z: statements at least 21 days before the due date)
• 12 CFR 1026.53, CFPB (Regulation Z: how payments above the minimum are applied)
• 12 CFR 1026.55, CFPB (Regulation Z: limits on rate increases)
• A box on my credit card bill says I will pay off the balance in three years..., CFPB
• The worked examples are our own calculations: a fixed 22.36% APR, interest worked out monthly, no new charges and no fees.