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 What Smart Investors Know Smart investors take the time to separate emotion from fact. A Taxing Story: Capital Gains and Losses Understanding how capital gains are taxed may help you refine your investment strategies. Taxable vs. Tax-Deferred Savings Use this calculator to compare the future value of investments with different tax consequences.