If you're carrying a balance on a credit card and paying interest on it, a 0% balance transfer card allows you to move that debt to a new card where no interest is charged for a set promotional period. This means repayments go toward reducing the balance rather than servicing interest, for as long as the 0% period lasts.

It's worth knowing that 0% periods can vary massively between providers on these cards. However, don't assume that the longer the interest-free period, the better. Opting for a card with a shorter 0% period might be a cheaper option. Here's why.

How do balance transfer credit cards cards work?

Balance transfer cards are specialist types of plastic that repay debts on old cards for you. When you apply for a balance transfer card you'll be given the option of transferring debts over from your old card. The amount you can transfer will depend on the credit limit you are offered.

Once you've shifted debt, you'll owe your new card instead. Crucially, the market-leading balance transfer cards come with decent 0% periods. This means you won't have to pay interest on anything you transfer over for the full duration of the 0% period.

Interest-free periods vary between cards, with the longest deals offering more than TWO YEARS at 0% . While, you may think it's best to go for the longest 0% period possible, this isn't always the case. Before we explain why, let's take a look at how balance transfer cards work.

How do 0% lengths on 0% balance transfer credit cards work?

When you're accepted for a 0% balance transfer credit card, you have the power to move over debt you have on other credit cards. Anything you shift across will be transferred to your new balance transfer card, meaning you'll benefit from a shiny new interest-free period. This means you won't have to pay any interest for the length of the 0% period, as long as you follow the main balance transfer rules (we explain these below).

As of July 2026, the longest 0% balance transfer period available in the UK market is up to 38 months, though the actual length offered to an individual applicant may be shorter depending on their credit profile; for example, some applicants accepted for the longest cards receive 32 or 35 months rather than the full 38. Other providers offer periods of up to 36 months.

Transfer fees on the longest deals typically run between 3.1% and 3.49% of the balance moved. It's worth noting that some cards advertise a guaranteed 0% period (meaning all accepted applicants receive the full advertised length) while others advertise an "up to" figure with a shorter fallback rate for some applicants. The market in this area moves quickly, and the providers offering the longest deals can change (July 2026).

Always make sure you can afford repayments.

What are the main rules to follow when it comes to balance transfer credit cards?

If you're planning to get a balance transfer credit card, it's important to understand that there are some very important rules to follow. If you fall foul of any of these rules, you could lose any 0% deal, or face the prospect of having to pay hefty interest.

1. Never spend (or withdraw cash) on these cards

Unless otherwise stated, the 0% rate on balance transfer credit cards typically only applies to transferred debt. So, if you use a balance transfer card for purchases, or a cash withdrawal, you'll probably be hit with hefty interest. Therefore, only ever use a balance transfer card to shift existing debt to 0%.

If you are looking for a credit card to finance a new purchase, take a look at ourbest 0% purchase credit cards guide.

2. Always make at least the minimum monthly payment

While balance transfer credit cards often come with decent 0% periods, you usually still have to make the minimum monthly payment to keep the interest-free period alive. In other words, "0%" doesn't mean you've nothing to pay. If you're concerned about this rule, you may wish to set up an automatic direct to make the minimum payment as soon as you're accepted for a card.

3. Plan to clear your balance within the 0% period

If you're accepted for a balance transfer card pay close attention to the length of the 0% period. Always plan to clear your debts before the interest-free period ends. If you don't, you'll have to start paying interest.

While you'll need to make at least the minimum monthly payment to keep your 0% deal alive (as explained above), clearing your balance before the interest-free period ends will mean paying MORE than the minimum.

If you cannot clear your balance before the end of the 0% period, the next-best thing is to apply for a new 0% balance transfer card. However, you shouldn't bank on being able to do this. That's because there's no guarantee you'll be accepted for another card in future. Also, the balance transfer market may look very different in future. For example, it's possible that 0% deals may be far less generous in a year or so.

4. You usually have to shift your balance within a set period to get the headline 0%

Most balance transfer credit cards will stipulate that in order to grab the headline 0% rate, you must transfer your balance within a set period. This is usually 30 days or so, though it varies between providers. Always study the terms of any offer before applying for a card. If you don't, there's a risk you'll miss out on a 0% deal.

5. Don't shift debt from a card within the same banking group

Balance transfer providers usually don't allow you to transfer debts from a card within the same banking group. For example, you won't be allowed to shift debt from a Halifax card to a Lloyds card as they're part of the same group. If you're unsure about which banks belong to the same group, pay attention to the terms of any balance transfer offer at the time of application. Usually it will be spelled out which providers are part of the same group.

What about a shorter 0% balance transfer card?

When comparing balance transfer credit cards, you may be tempted to apply for the longest card possible. This certainly isn't a bad idea if you think you'll need a very long time to clear you existing debt.

However, it's important to note that the longest cards often charge a one-off fee. This is usually a percentage of the debt you wish to transfer. Unsurprisingly, the highest fees are usually attached to the cards for the longest 0% periods.

For those who can clear their balance within a shorter timeframe, fee-free balance transfer cards are worth being aware of. These typically offer shorter 0% periods than the longest deals on the market, but no transfer fee applies.

To illustrate the current market: the longest 0% balance transfer period currently available is 38 months, though the leading cards at this length charge a transfer fee of around 3.45% to 3.49% of the amount moved. In contrast, fee-free balance transfer cards currently offer 0% periods of up to around 12 months.

As an illustration of the potential fee saving: on a £5,000 balance, a 3.49% transfer fee would cost £174.50. If the balance can be cleared within a shorter fee-free deal, that cost is avoided entirely. Whether this trade-off makes sense depends on the size of the balance, the time needed to clear it, and the specific terms available to the individual applicant.

Remember, balance transfer deals can change regularly. To see a list of the top cards available, take a look at our best balance transfer credit cards guide.

Always make sure you can afford repayments.