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.

Editor's Note: APYs listed in this article are up-to-date as of the time of publication. They may fluctuate (up or down) as the Fed rate changes. Select will update as changes are made public. Some ...