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Ask how does credit card work and almost every guide gives you the same answer: you borrow, you repay, you pay interest if you are late. That is accurate and it misses the single most valuable thing a UK credit card does.
Pay for something costing more than £100 on a credit card and the card company becomes jointly liable with the retailer if anything goes wrong. It is called Section 75, it is written into UK law, it costs nothing, and a debit card does not give it to you.
This article explains how credit cards work in the UK. It is general information, not financial advice — for guidance on your own circumstances, speak to a regulated adviser or use the free MoneyHelper service linked at the end.
How Does Credit Card Work: the basic mechanism
A credit card is a revolving credit facility. The provider sets a credit limit, and you can borrow up to that limit repeatedly as you repay it.
Each month you receive a statement showing what you have spent, the minimum amount you must pay, and the date you need to pay it by. What happens next depends entirely on which of two choices you make.
- Pay the statement in full — MoneyHelper’s guidance is that if you repay the full amount, you will not pay interest on anything you have spent. The borrowing was effectively free.
- Pay less than the full amount — you then pay interest on everything you owe, added to your next statement.
That is the whole machine. Everything else is detail on top of those two outcomes.
The mistake: treating the minimum payment as the bill
The minimum payment is the amount that keeps your account in good standing. It is not a suggestion of what you should pay, and paying it does not mean you have handled the bill.
MoneyHelper puts the cost plainly: interest rates are typically between 25% and 60%, “so this can be expensive”, and only paying the minimum “can mean it takes years to clear your debt”.
Those rates are why the gap between the two choices above is so large. The same card is either free credit or some of the most expensive borrowing available to a consumer, and the only thing separating them is whether you clear the statement.
One exception worth knowing: cash withdrawals are treated differently. MoneyHelper notes you still pay interest on cash withdrawals even when you repay the full amount, so taking cash out on a credit card starts charging immediately.
Section 75: the protection most guides skip
This is the part that makes a credit card genuinely different from a debit card, and it is the strongest practical reason to put a large purchase on one.
Under Section 75 of the Consumer Credit Act, your card provider is jointly liable with the retailer. If the goods never arrive, the company goes under, or the item is not as described, you can claim against your card provider.
- The item must cost more than £100 and up to £30,000. The £100 applies to the individual item, not your total spending.
- You do not have to pay the whole amount on the card. Paying just the deposit by credit card can be enough to bring the purchase into scope.
- It does not apply to debit cards. This protection is specific to credit.
- It is free. There is nothing to opt into.
The deposit rule is the one people find most surprising. Put a £200 deposit on a card for a £3,000 sofa and pay the rest by transfer, and the purchase can still be covered.
Section 75 is not the same as chargeback
These are often confused. Section 75 is legal protection under UK law. Chargeback is an agreement that Visa, Mastercard and American Express have signed up to — an industry scheme rather than a statutory right.
Chargeback does cover debit cards, which Section 75 does not, but it operates to a time limit — MoneyHelper gives a 120-day claim window from purchase. Section 75 provides the broader legal liability.
What you are actually charged, and when
Interest is the main cost, but it is not the only one.
- Interest on unpaid balances — charged on everything you owe once you pay less than the full statement.
- Interest on cash withdrawals — applies even if you repay in full.
- Late payment fees — MoneyHelper notes that paying late typically triggers a late fee, and you might lose special deals such as a low interest rate.
- Damage to your credit file — late payment is recorded and affects future borrowing.
A 0% introductory offer changes the interest picture for a defined period only. When it ends, the standard rate applies to whatever is left, which is why these offers reward people who clear the balance before the deadline.
How a credit card differs from a loan
The two are often compared, but they behave differently in ways that matter.
| Credit card | Personal loan | |
|---|---|---|
| How you receive it | A limit you draw on repeatedly | A fixed sum, once |
| Repayment | Flexible, with a monthly minimum | Fixed instalments over a set term |
| Interest | Avoidable if you clear the statement | Charged from the start |
| Section 75 cover | Yes, within the thresholds | Not applicable in the same way |
A card is built for short-term, repeatedly-repaid borrowing. A loan is built for a known amount over a known period. Using a card as a substitute for a loan — carrying a large balance for years at card interest rates — is where the cost becomes serious.
Credit utilisation and your credit score
Credit utilisation is the proportion of your available limit you are using. Running close to your limit signals strain to lenders, and a widely used rule of thumb is to keep utilisation comfortably below a third of your limit.
Two points that are less widely understood. Paying in full every month still builds a positive repayment history — you do not need to carry a balance to build credit. And closing an old card reduces your total available credit, which can push your utilisation percentage up even though your spending has not changed.
What the numbers on the card mean
The long number identifies the issuer and your account. The expiry date limits the card’s validity. The three digits on the signature strip are the CVV, a security code used to show the card was in your possession for online and telephone purchases.
The CVV is deliberately not stored in the magnetic stripe or chip, which is why a legitimate retailer asks for it at checkout but should never store it afterwards. Nobody legitimate needs it by email or over the phone unprompted.
Frequently Asked Questions (FAQs)
How does a credit card work in simple terms?
You borrow up to a set limit, receive a monthly statement, and choose whether to repay it in full. Repay in full and you generally pay no interest on purchases. Repay less and interest is charged on everything you owe.
What is Section 75 and why does it matter?
It makes your credit card provider jointly liable with the retailer on purchases costing more than £100 and up to £30,000. If the retailer fails to deliver or goes out of business, you can claim against your card provider. Debit cards do not carry this protection.
Do I have to pay the full amount on the card for Section 75?
No. Paying a deposit by credit card can be enough to bring the purchase within scope, even when you pay the balance another way.
What happens if I only pay the minimum?
You stay in good standing but pay interest on the full outstanding balance. With rates typically between 25% and 60%, MoneyHelper warns this can take years to clear.
Does paying in full hurt my credit score?
No. Paying in full each month builds a record of on-time repayment. You do not need to carry interest-bearing debt to build credit.
Why am I charged interest on cash withdrawals even when I pay in full?
Cash withdrawals are treated separately from purchases and interest applies to them regardless of whether you clear your statement.
What is the difference between chargeback and Section 75?
Section 75 is UK legal protection specific to credit cards. Chargeback is a scheme agreed by Visa, Mastercard and American Express, covers debit cards too, and operates within a claim window — MoneyHelper gives 120 days from purchase.
How much of my credit limit should I use?
A common rule of thumb is to stay below roughly a third of your available limit. Running consistently close to the limit can weigh against you when lenders assess your file.
Sources
- MoneyHelper — A simple guide to credit cards
- MoneyHelper — Section 75 and chargeback protection
