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 Inflation and Your Portfolio Even low inflation rates can pose a threat to investment returns. The Ivory Tower Changes Wall Street Thanks to the work of three economists, we have a better understanding of what determines an asset’s price. Taxable vs. Tax-Deferred Savings Use this calculator to compare the future value of investments with different tax consequences.