Revolving balances are a specific kind of debt on a credit card or other Line of credit carried over from month to month with interest being charged on the outstanding amount. Usually, you must pay back the amount borrowed, plus interest, when using a credit card to make a purchase or draw money from a line of credit. Any outstanding debt not paid in full by the due date each month is carried over to the next month and is subject to interest charges. The revolving balance refers to this outstanding debt.