Credit cards are a convenient way to borrow money, but they can also be one of the most expensive forms of credit if balances are not repaid quickly.
Many people know their credit card has an interest rate, but fewer understand how that interest is actually calculated. Once you understand how it works, it becomes much easier to see why credit card debt can grow so quickly.
What Is Credit Card Interest?
Credit card interest is the cost you pay for borrowing money from the credit card provider.
Each card has an interest rate, usually shown as an APR (Annual Percentage Rate). The APR represents the yearly cost of borrowing if you carried a balance for a full year.
For example:
- Credit card balance: £1,000
- APR: 24%
If the balance remained unpaid for a year, you would roughly pay £240 in interest.
However, interest is usually applied daily, not once per year.
Daily Interest Explained
Credit card companies normally calculate interest using a daily interest rate.
To find the daily rate, the APR is divided by 365.
Example:
- APR: 24%
- Daily interest rate: about 0.065% per day
If you owed £1,000 on your card, the interest added each day would be roughly:
£0.65 per day
That might not sound like much, but over time it adds up quickly.
When Credit Card Interest is Charged
Interest is usually charged when you carry a balance from one month to the next.
If you pay your full statement balance by the payment due date, most credit cards charge no interest on purchases.
However, if you only make the minimum payment, interest will normally be added to the remaining balance.
This is why paying off the full balance each month is the cheapest way to use a credit card.
Why Minimum Payments Keep You in Debt
Credit card statements include a minimum payment, which is the smallest amount you must pay to keep the account up to date.
Minimum payments are often calculated as:
- Around 1% to 3% of the balance, plus interest and fees
While this keeps the account active, it does very little to reduce the actual debt.
For example:
| Balance | Minimum Payment | Interest Rate |
|---|---|---|
| £2,000 | £60 | 29% APR |
If you only make minimum payments, most of that payment goes toward interest, not reducing the balance.
This is one of the main reasons credit card debt can last for many years.
Compound Interest
Credit card interest also compounds.
This means interest is charged on interest if the balance is not cleared.
Example:
Month 1
Balance: £1,000
Interest added: £20
New balance: £1,020
Month 2
Interest is calculated on £1,020, not the original £1,000.
Over time this can significantly increase the total amount owed.
Different Interest Rates on the Same Card
Many credit cards have different interest rates depending on how the money was borrowed.
For example:
| Transaction Type | Typical Interest Rate |
|---|---|
| Purchases | 20%–30% APR |
| Balance transfers | Sometimes 0% for a promotional period |
| Cash withdrawals | Often higher, sometimes 30%+ APR |
Cash withdrawals are usually the most expensive because interest starts immediately, without any interest-free period.
How to Reduce Credit Card Interest
If you are dealing with credit card debt, there are several ways to reduce the amount of interest you pay.
Pay More Than the Minimum
Even small extra payments can make a significant difference over time.
Focus on the Highest Interest Cards First
Paying off the card with the highest interest rate first can reduce the total interest you pay.
Consider a Balance Transfer
Some cards offer 0% balance transfer periods, which can temporarily stop interest while you repay the balance.
Avoid New Spending
Adding new purchases while trying to repay debt can slow down progress.
Why Understanding Interest Matters
Credit card interest can make debt last far longer than people expect.
Without understanding how interest works, it is easy to believe that regular payments will quickly reduce the balance. In reality, a large portion of those payments may simply be covering interest.
Once you understand the mechanics of credit card interest, it becomes easier to make decisions that reduce the total cost of borrowing and help you clear debt faster.
