Rule of 70 Helps Estimate When Retirement Savings Double

The Rule of 70 is a quick way to estimate when money might double.

You divide 70 by the yearly return rate.

For example, a 7% return suggests that money could double in about 10 years.

A 10% return suggests it could double in about seven years.

Starting earlier can give savings more time to grow.

The estimate works best when returns stay fairly steady.

It may be inaccurate for investments whose values change often, such as equities or mutual funds.

Adding or taking out money can also change the result.

People should use the rule as a starting point, not as a complete retirement plan.