The Rule of 70 is a mathematical formula used to estimate the time it takes for an investment or any quantity to double, given a fixed annual growth rate. This rule is used by investors and financial ...

If you try to withdraw early from just about any retirement plan, you'll be slapped with a penalty—an incentive to leave your money alone and let it build toward retirement like you always intended.

The Rule of 70 and the Rule of 72 are two popular shortcuts that can help investors quickly estimate the doubling time of an investment. These rules are particularly useful for grasping the potential ...