The Rule of 72 calculator is a useful tool for estimating the time it takes for an investment to double based on a given interest rate. By dividing 72 by the interest rate, the calculator provides an approximate number of years required for the investment to double in value. This rule offers a quick and easy way to understand the power of compounding and the impact of interest rates on investment growth. The Rule of 72 calculator allows individuals to experiment with different interest rates and gain insights into the potential growth of their investments. Whether for personal finance planning or investment decision-making, this calculator helps users assess the time horizon for achieving their financial goals and make informed choices about their investment strategies.