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 16 Wall Street Cliches in 60 Seconds Pundits say a lot of things about the markets. Let's see if you can keep up. Estimating the Cost of College This worksheet can help you estimate the costs of a four-year college program. How Compound Interest Works Use this calculator to better see the potential impact of compound interest on an asset.