Compound interest can help turbocharge your savings and investments, or it can quickly lead to an unruly balance, keeping you stuck in a cycle of debt. Its magic can help you earn more — or owe more.

Compound interest is interest that's calculated on both the initial principal of a deposit or loan and on all accumulated interest. It's a tremendous advantage for savers and investors but not so much ...

Interest can be charged when you borrow money or earned when you save. When you charge something on a credit card or take out ...