Did You See The Big Difference The Roi makes? At 2%, it takes you 36 years to double your money. At 4%, it takes you 18 years to double your money. At 10% in takes you 7.2 years to double your money. At 13% it takes you 5.5 years to double your money. Understanding the Rule of 72 helps you compare investment opportunities Here's another good use of the Rule of 72: It can tell you what rate of return you need to double your money in a certain number of years. To determine the ROI you need to double your money in a certain number of years, just divide 72 by the number of years. Example: I need to double my money in four years. What ROI do I need on my money? 72 divided by four years = 18 You would need to have an 18% ROI if you want to double your money in four years now, you try it: What "ROI would I need if: % ROI 1) "I need to double my money in 10 years." % ROI 2) "I need to double my money in 8 years." Submit