A balance transfer credit card can offer you many months to pay off high-interest debt in the form of a 0% introductory APR. But when that balance transfer period ends, interest charges are added to the balance if it isn’t paid off.

To avoid paying interest on your transferred balance, aim to have it paid in full when the promotional period ends. If that’s not possible, you’ll have to come up with a plan to wipe out the remaining balance before the interest charges pile up.

What happens when the balance transfer offer expires?

The APR or annual percentage rate on a credit card represents the interest you’re charged on your card’s balance over a 12-month period. Introductory offers—as the name suggests—are special offers from credit card issuers that last for a specified period of time. Once that time period ends for your balance transfer credit card, the card’s ongoing APR will apply to your remaining credit card balance.

The higher the credit card balance is when the 0 percent APR period ends, the more interest you will accrue. Let’s say you have $1,000 left on your credit card at the end of your introductory offer. If the regular APR is 24 percent and you decide to pay $100 per month until your balance is zero, it will take you twelve months to get there. In addition to the $1,000 you borrowed, you will pay $127 in interest. Try your own numbers in Bankrate’s credit card payoff calculator.

What to do if you still have debt after your balance period transfer ends

The best course of action when you have a balance on your credit card is to pay it in full at the end of your billing cycle. But if you’re approaching the end of your promotional 0 percent APR period and still have a balance, there are a number of moves you can make:

Leave the balance on the current credit card and revamp your payment plan

If you’re unable to pay your card’s balance in full and don’t want to apply for another card, make a new plan to pay the current card balance. Address any budgeting issues that may be preventing you from tackling your credit card balance, and try to pay the balance off as quickly as you can. This is an expensive option, as the average credit card interest rates on most balance transfer cards are relatively high.

Make a lump sum payment

Making a lump sum payment is your simplest and least expensive option if you have a balance remaining when your balance transfer period ends. You’ll avoid any interest charges by using any savings or extra cash you may have to off the balance transfer card. Consider how much—if any—cash on hand you’ll need in the near future and weigh that against your need to pay down your credit card balance.

Consider a debt consolidation loan

A debt consolidation loan could be a helpful tool to help you manage your debt. It allows you to use one loan to pay off multiple high-interest debts—typically credit cards—over a period of time with fixed monthly payments. If the interest rate on the loan is less than the APR on your current balance transfer card, you’ll see some savings.

Transfer the balance to another 0% card

It’s possible to transfer your existing balance to another 0 percent APR balance transfer credit card when your current card’s balance transfer period ends. This gives you the opportunity to pay the balance off interest-free for a second time. There’s no official limit to how many balance transfer cards you can sign up for, but individual credit card issuers may have their own rules.

Keep in mind you’ll need to pay another balance transfer fee and that your credit will be pulled each time you apply for a new card, which could lower your credit score. It also won’t lower the amount you owe or address any issues that might be causing you to carry credit card debt.

The bottom line

The best balance transfer credit cards can potentially save you hundreds in interest. Paying your balance in full before the introductory period is over should be your main goal when transferring a balance. If that’s not possible, it’s critical to create a backup plan. If you didn’t have a plan going into using your balance transfer credit card the first time around, you can still successfully manage your credit card debt with the right strategy.