Credit card interest is expensive because it is charged on a revolving balance at a high rate, usually 18% to 30% a year. The good news is that the maths is simple, and once you see how it works, you can pay a balance off far faster than the lender's minimum payment schedule suggests.

How Card Interest Is Calculated

Most cards quote an annual percentage rate (APR) and charge interest daily. The daily periodic rate is the APR divided by 365. At 22% APR, the daily rate is about 0.0603%. Each day, that rate is applied to your balance, and the interest is added to what you owe at the end of the billing cycle. For a quick estimate, you can divide the APR by 12 to get a monthly rate: on a 3,000 balance at 22%, that is roughly 55 of interest per month.

Many cards have a grace period. If you pay the full statement balance by the due date every month, you usually pay no interest on new purchases. Once you carry a balance, the grace period normally disappears, and interest applies to new purchases from the day you make them.

What a Fixed Payment Really Does

Take a 3,000 balance at 22% APR with no new purchases. How long it takes depends almost entirely on how much you pay each month:

  • Paying 100 a month clears the balance in about 44 months and costs roughly 1,400 in interest.
  • Paying 150 a month takes about 25 months and costs roughly 770 in interest.
  • Paying 300 a month takes about 11 months and costs roughly 340 in interest.

Tripling the payment does not just triple the speed. It cuts the interest to about a quarter, because the balance falls faster and less is charged each month. Our guide to how to calculate loan EMI explains the formula behind these figures.

Why Minimum Payments Trap You

Many cards set the minimum payment as a small percentage of the balance, such as 2%, with a small floor. As the balance falls, the minimum falls with it, so the payments never speed up. On the same 3,000 balance at 22%, paying only 2% of the balance each month (with a floor of 25) would take more than 50 years and cost over 21,000 in interest. The exact formula varies by issuer and country, but the lesson is the same: a minimum payment is designed to keep the account profitable, not to clear it.

Avalanche vs Snowball

If you have several cards, there are two popular strategies. In both, you pay the minimum on every card and put all the extra money toward one target.

  • Avalanche: target the card with the highest interest rate first. This is mathematically the cheapest.
  • Snowball: target the card with the smallest balance first. You clear accounts sooner, which many people find motivating.

Here is an example. You owe 1,500 at 24%, 3,000 at 18% and 800 at 12%, and you can pay 400 a month in total with a minimum of 25 on each card. Both methods clear everything in about 15 months. The avalanche costs about 623 in interest and the snowball about 690, a difference of around 66. The gap is modest, so the best method is the one you will actually stick with.

Practical Steps to Cut the Cost

  • Stop adding new purchases to a card you are paying down, or you will be running to stand still.
  • Ask your issuer for a lower rate. If your credit has improved, it is worth a call.
  • Consider a balance transfer card with a low or zero introductory rate, but check the transfer fee, which is often 3% to 5%, and the date the promotional rate ends.
  • Pay more than the minimum every month, even by a small amount, and pay on the day your salary arrives.
  • Avoid cash advances. They usually have a higher rate, a fee, and no grace period.
  • Set up automatic payments so a missed due date never adds a late fee or damages your credit score.

What to Do If You Cannot Keep Up

If you are already struggling, contact the issuer before you miss a payment. Many offer hardship plans with reduced rates or fixed repayment schedules. Non-profit credit counselling services in many countries can help you build a repayment plan for free or at low cost. Be cautious of companies that charge large upfront fees to settle your debts.

Frequently Asked Questions

Is credit card interest compounded?

Yes. Interest is added to the balance, and the next period's interest is calculated on the larger amount. That is why a card at 22% APR with daily compounding has an effective annual rate of about 24.6%. See our guide to compound and simple interest for more.

Does paying the full balance each month cost anything?

If you pay the full statement balance by the due date, you generally pay no interest on purchases, though some cards charge an annual fee.

Before You Start

Write down every card with its balance, APR and minimum payment, decide how much extra you can add each month, and pick avalanche or snowball. Then use our Loan / EMI calculator to see how the payoff time changes when you raise the payment.