Guide · 4 minute read · Updated 10 Jul 2026

How do 0% balance transfer credit cards work?

A balance transfer moves debt from a card charging interest onto a new card that charges none for a set window. Done right it can save hundreds; the whole game is clearing the balance before the 0% ends and not treating the freed-up space as new spending money.

What a balance transfer actually does

You apply for a new card advertising a 0% balance transfer deal, then ask it to pay off the balance on your existing card. The debt does not disappear, it just relocates to a card that stops charging interest for a fixed number of months. Every pound you pay in that window goes straight at the balance instead of being eaten by interest.

The saving can be large. Move £3,000 off a card at 24.9% APR and you would otherwise pay roughly £700 in interest over a year. On a 0% transfer, that £700 stays in your pocket, minus a one-off fee. If you are only ever making minimum payments, see the minimum payment trap for why a transfer often breaks the cycle that keeps you stuck.

The transfer fee and the promo window

Two numbers decide whether a card is any good: the fee and the length. Most longer 0% cards charge a one-off transfer fee of roughly 2% to 4% of the balance moved, commonly around 3% on the longest deals. On a £3,000 transfer, a 3% fee is £90 added to your balance up front. There are shorter fee-free cards (around fourteen months at 0% with no fee), which suit smaller balances you can clear quickly.

The 0% period is the deadline. The longest deals stretch to around 36 months, but many are shorter, and headline figures are usually "up to", meaning the term you are actually offered depends on your credit profile. When the 0% ends, any leftover balance starts attracting the card's standard rate, often around 24% APR, so the plan has to be to clear it before that date, not on it.

How to use one properly

Divide the balance plus the fee by the number of 0% months and pay at least that every month by direct debit. A £3,090 balance over 30 months is about £103 a month; pay that and you finish exactly as the offer expires, interest-free. The debt payoff planner turns any balance and window into a monthly target.

Two rules keep you out of trouble. First, always pay at least the minimum on time, because a single missed payment can void the 0% deal entirely and snap the full interest rate back on. Second, do not spend on the card. Purchases usually are not covered by the same 0% offer and can be charged at the purchase rate, and the way payments are allocated can leave that pricey debt sitting there longest. Treat the card as a debt to kill, not a wallet.

Eligibility and the credit impact

Balance transfer cards, especially the longest 0% deals, tend to want a solid credit record, so the best terms go to people who least need them. Many lenders offer an eligibility checker that uses a soft search, which shows your likely chance of approval without leaving a mark; use one before you formally apply.

Applying does leave a hard search and a new account, which can dip your score briefly. Against that, moving debt to 0% and paying it down steadily lowers your credit utilisation, which usually helps over time. One thing you cannot do is transfer a balance between two cards from the same bank or group, so a Barclaycard balance will not move to another Barclaycard.

Common questions

Is a balance transfer fee worth paying?

Usually yes. A typical 3% fee on £3,000 is £90, while a year of interest at 24.9% on the same balance is around £700. As long as you clear the balance inside the 0% window, the fee is a fraction of the interest you avoid.

What happens when the 0% balance transfer period ends?

Any balance still on the card starts being charged at the card's standard rate, often around 24% APR. That is why the aim is to clear the whole balance before the 0% period expires, by dividing it (plus the fee) across the promo months and paying that each month.

Can I spend on a 0% balance transfer card?

You can, but you usually should not. New purchases are often charged at the standard purchase rate rather than 0%, and payment allocation rules can leave that expensive debt on the card longest. Keep the card strictly for the transferred balance and use a different card for spending.

Will a balance transfer hurt my credit score?

Applying leaves a hard search and a new account, which can dip your score briefly. Over time, moving debt to 0% and paying it down cuts your credit utilisation, which tends to help. Use an eligibility checker with a soft search before applying to avoid a wasted hard search.

Guidance and education, not regulated financial advice.