The Rule of 72 Do you know how long it may take for your investments to double in value? The Rule of 72 is a quick way to figure it out. Share | Related Content Jane Bond: Infiltrating the Market Agent Jane Bond is on the case, cracking the code on bonds. What’s Your Investment IQ? You make decisions for your portfolio, but how much do you really know about the products you buy? Try this quiz What Is the Dividend Yield? This calculator helps determine your pre-tax and after-tax dividend yield on a particular stock.