The Rule of 72 is a simple mathematical formula used to estimate the number of years it will take for an investment to double in value. To use the Rule of 72, you divide 72 by the annual rate of return on your investment. For example, if you have an investment that earns a 6% annual return, it would take approximately 12 years for your investment to double (72 divided by 6 equals 12). This rule is a handy tool for quickly estimating the impact of compound interest on your investments. It is a rough approximation and works best for interest rates between 6% and 10%. Anything below or above this range may require a more precise calculation. Understanding the Rule of 72 can help investors make informed decisions about their investments and better understand the power of compound interest over time. By using this rule, investors can quickly determine how long it will take for their money to double and plan their investment strategies accordingly.