What type of debt is characterized by a fluctuating amount as the borrower utilizes credit?

Revolving debt is characterized by its fluctuating amount because it allows the borrower to utilize credit up to a certain limit and pay it down at their discretion. This type of debt is often seen in credit cards or lines of credit, where the borrower has access to a set amount of funds but only pays interest on the amount they have borrowed at any given time. As the borrower uses the credit, the balance increases, and as they make payments, the balance decreases, creating a cycle of borrowing and repayment that adjusts over time. This flexibility is what distinguishes revolving debt from other types such as installment debt, where payments and total borrowed amounts are fixed, or fixed-rate debt, which has static terms that do not change. Secured debt involves collateral but does not inherently have the fluctuation characteristic that defines revolving debt.