0% balance transfer cards: how they work and the traps to avoid

A 0% balance transfer card lets you move debt from a card charging interest to one that charges none for a set period. Used well, every pound you pay goes to clearing the balance rather than to interest. Used badly, it becomes another card with a balance on it. This guide explains the mechanics and the mistakes to avoid. Information only, not personal advice.

How a balance transfer works

You apply for a new card. Once approved, you ask the new provider to pay off some or all of the balance on your old card. The debt now sits on the new card at 0% interest for the promotional period. You make at least the minimum payment each month. When the 0% period ends, any remaining balance is charged at the card's standard rate, which is often above 20% APR.

Most cards require you to make the transfer within a set window after opening, often 60 to 90 days. Miss that window and the 0% rate on transfers may no longer apply.

The transfer fee

Almost all 0% cards charge a fee on the amount transferred, typically a low single-digit percentage. Moving £3,000 with a 3% fee costs £90, added to your balance. Longer 0% periods usually carry higher fees. A shorter deal with a lower fee can be cheaper if you can clear the debt in time, so match the length to how fast you can realistically repay. Check a comparison site for the current deals and fees.

Eligibility checkers and soft searches

Every full credit application leaves a hard search on your credit file, and several in a short time can lower your score and put off lenders. Before you apply, use an eligibility checker. These run a soft search, which you can see but lenders cannot, and tell you how likely you are to be accepted and sometimes what limit and 0% length you would get. Only apply once you have a strong indication of acceptance.

You will usually not be able to transfer a balance between two cards from the same banking group, so check who owns the card you are moving from.

The spending trap

The 0% rate is for the transferred balance. New purchases are often charged at the standard rate from day one, and some cards apply your payments to the cheapest debt first, leaving the expensive purchases untouched. The safest approach is to treat the card as a repayment vehicle only. Put it away, do not add it to your phone wallet, and use a different card or debit card for spending.

Clearing it before the 0% ends

Divide the balance by the number of months of 0% and set that as your monthly payment by direct debit. For £3,090 over 24 months that is around £129 a month. Paying only the minimum will leave most of the debt in place when the rate expires.

Put the end date in your calendar with a reminder two months before. If you will not clear the balance in time, you can often transfer the remainder to another 0% card, paying another fee. That is better than paying interest, but it is not a plan. The aim is to leave the cycle, not to stay in it.

Watch out for

• Missing a payment. One late payment can cancel the promotional rate on many cards.
• Closing the old card immediately. Check the balance is fully cleared and any residual interest has been paid first, then close it so you are not tempted to run it back up.
• Transfers above your new limit. Providers often cap transfers at 90% to 95% of the credit limit.
• Cash withdrawals and money transfers to a bank account. These are separate products with their own rates and fees.
• Using the freed-up space on the old card. The point is to reduce total debt, not to double it.