Balance transfers: how they work and where they catch people out

Resources · Paying off debt · 5 min read Advanced

Key points

• A balance transfer moves debt from one card to another, usually at a low or 0% rate for a set time.
• Most charge a transfer fee, and the rate rises when the promotional period ends.
• The saving depends on how much of the balance you clear before the promotion ends.
• New spending, missed payments and fine print are where people most often get caught out.

How a balance transfer works

A balance transfer card offers a low or 0% interest rate on debt you move onto it from another card. That low rate only lasts for a set promotional period. After that, whatever’s left gets charged the card’s standard rate, often called the revert rate.

You’ll usually pay a one-off transfer fee too. It’s a percentage of the amount you move, and it gets added straight onto your new balance.

The details vary a lot between products and countries. Promotion length, fees, revert rates, even how your payments get applied. What counts is the terms of the specific offer in front of you.

A worked example

Say you owe $5,000 on a card at 22% a year. You move it to a card that charges a 3% transfer fee, with 0% interest for 15 months and 22% after that. The maths works the same in any currency.

The assumptions: the $150 fee is added to the balance, making $5,150. Interest is charged monthly at the yearly rate divided by 12, on the balance before that month’s payment. Payments are fixed. No new spending goes on either card. The last payment is whatever clears the balance.

The transfer costs less than staying put in every row. But look how much the gap changes. Pay about $344 a month (with a smaller final payment) and you clear the lot inside the 0% period, so the fee is your only cost. Pay $150 and you’ve still got $2,900 left to start charging 22% in month 16.

Here’s the number to work out for yourself: your balance after the fee, divided by the promotional months. In this case, $5,150 ÷ 15 is $343.33 a month.

Where people get caught out

The balance outlasts the promotion.
This is the big one. Once a leftover balance hits the revert rate, much of the benefit can vanish. Some people end up moving the debt again and paying a second fee.

New spending on the card.
Purchases on a balance transfer card often don’t get the promotional rate. And in some places, the minimum payment can be applied to the cheapest balance first. So new spending can sit there at a high rate while you chip away at the 0% part.

The old card fills up again.
Moving a balance clears the old card. Use it again and you’ve got two debts instead of one.

Missed or late payments.
On some cards, a late payment can end the promotional rate early or add fees. In the US, this can only happen once a payment is 60 days late. Setting up automatic payments of at least the minimum helps you avoid that.

Deferred interest offers.
Some promotions, particularly some store financing, use “deferred interest”. If any balance is left when the promotion ends, interest can be charged all the way back to the start date. That’s not the same as a true 0% rate. Look for the wording in the terms.

Paying only the minimum.
Minimum payments on a 0% balance can be tiny. Stick to them and you won’t clear the debt in time, for the same reasons minimum payments take so long on any card.

The fee itself.
You pay the transfer fee up front. If you’d clear the debt quickly anyway, or the balance is small, the fee can cost more than the interest you save.

Approval and limits.
Balance transfer cards usually involve a credit check. And the limit you get may be lower than your balance, so only part of it moves across.

Questions to ask yourself before deciding

Start with the basics: what’s the fee, how long is the promotion, and what’s the revert rate? Then work out the monthly payment that would clear the full balance within the promotion. Can you really manage it every month?

If you can’t clear it all, figure out what the leftover will cost at the revert rate. Be honest about the old card, too. Will you actually stop using it? And check whether the promotion is a true 0% rate or deferred interest.

For some people, a transfer saves real money and gives them a hard deadline to work toward. For others it just adds complications. Your numbers and your habits decide which camp you’re in. Comparing the total cost of credit can help you lay the options side by side.

Common questions

Is a balance transfer worth it?

It depends on the fee, the length of the promotion, and how much of the balance you can clear before the revert rate kicks in. In the worked example above, the transfer cost less than staying put at every payment level. But by very different amounts.

What happens when a 0% balance transfer ends?

Whatever’s left gets charged the card’s standard rate, often called the revert rate. If the offer used deferred interest, interest may be charged back to the start date.

Does a balance transfer affect your credit score?

Balance transfer cards usually involve a credit check, and how that’s recorded differs by country. Late or missed payments on the new card can also show up on your credit record.

Try it

Use the credit card payoff calculator to compare your current card with a lower rate. Then try the payment you’d need to clear the balance within a set number of months.

General information only, not financial advice. Your situation is your own.

Sources

• Regulation Z 1026.55, Limitations on increasing rates (CFPB), current version 2026