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 ...

The Rule of 72 is a shortcut or rule of thumb used to estimate the number of years required to double your money at a given annual rate of return and vice versa.

Interest can be charged when you borrow money or earned when you save. When you charge something on a credit card or take out a loan from a financial institution (student loan, auto loan, mortgage, ...