A balance transfer is when you move some or all of your credit card debt onto a single card that’s offering a lower interest rate for balance transfers. And that lower rate should then allow you to save money on interest as you focus on paying down your debt.

Lots of credit cards offer introductory 0% APRs for balance transfers, which last for a set amount of time. For example, you may see an offer advertising an introductory 0% balance transfer for 15 months, before the interest rate rises to a variable percentage that’s based on your credit. These balance transfer cards give you a window of time — which varies by card — to pay down your debt without adding to it with interest charges. But the balance transfer APR will jump once that window is up, and you will start being charged interest again.

A balance transfer offer could be a good idea if you have high-interest credit card debt. So it can buy you some time to pay down that debt, and you might be able to avoid interest charges while you do it. But in order to save the most with a balance transfer, it’s a good idea to have a clear plan in place to pay down the debt during the introductory balance transfer APR offer, so you don’t get stuck paying interest and end up with more debt than what you started with.

A balance transfer could also be a good idea if you’re juggling high-interest debt across multiple cards. It may be possible to transfer several balances to a balance transfer card, depending on the card issuer’s rules and how much you’re allowed to transfer. Consolidating your credit card debt can help you streamline multiple payments into one manageable payment.

There are several potential downsides to balance transfers. For one, many cards charge a balance transfer fee, which is a percentage of the amount you transfer or a flat dollar amount — whichever is higher of the two. So before you choose a balance transfer, make sure that the amount you can save on interest is at least worth this cost.

Also, if you intend to use the balance transfer card for new purchases as well, you could end up adding to your debt and paying more in interest. So if you don’t have a plan to pay off these new purchases, you may end up creating more problems for your finances.

And you may not be able to transfer all of your debt either. Balance transfer cards frequently limit the amount you can transfer, and some credit card issuers may not allow you to make transfers from the other accounts you have with them.

So before you decide on a balance transfer, read the fine print on the offers to check for any restrictions and or other potential downsides.

As with any credit card, who qualifies for a balance transfer card is determined by the issuer. Several factors will likely be considered, but one major component are your credit scores. To be approved for a balance transfer card, you may need to have good or excellent credit.

But having higher credit scores doesn’t mean you’ll automatically get approved. If you’re a Credit Karma member, you can use our Credit Karma Approval Odds to get an idea of how likely you are to be approved for a certain card. The Approval Odds aren’t a guarantee, but they can be a helpful tool to determine whether you might be likely to get approved while you’re researching your options.

Balance transfers may have a negative impact on your credit scores. When you apply for a new credit card, the issuer will run a hard inquiry on your credit reports. A hard inquiry can stay on your credit reports for up to two years, although the hard inquiry itself may lower your credit scores only for a few months.

A new credit card can also lower the average age of your accounts, which can have a negative impact on your scores.

But getting a new balance transfer card can also have a positive impact on your credit scores by lowering your credit card utilization rate (as long as you don’t increase your spending). Your credit card utilization rate is the percentage of your revolving credit you’re using at any given time.

If you choose a balance transfer, consider keeping all of your cards open (including the cards you transfer from) to show your positive payment history, boost your average age of accounts and help you maintain a low credit card utilization rate.