Bankrate on MSN

Rule of 72: What it is and how to use it

Here’s how the Rule of 72 works: Divide 72 by your expected annual interest rate (as a percentage, not a decimal). The answer is roughly the number of years it will take for your money to double. For ...
CNBC

Use this rule to quickly find out when your investments will double in value

When we put our money in the market, or before we even do, one of the biggest questions we have is: How long will it take for this investment to really grow? Luckily, there's a mathematical shortcut ...