The Rule of 72

The Rule of 72 is a simple yet powerful financial principle used to estimate the years required to double the value of an investment at a fixed annual rate of return or interest. By dividing 72 by your expected annual rate, you get a rough estimate of how many years it will take for your investment to double in value. Whether you're an investor wanting a quick gauge of your potential returns or someone new to the world of finance seeking to understand the power of compound interest, this calculator is designed to make the Rule of 72 more accessible and actionable for you. Input your expected annual interest rate, and let's discover the potential of your investments!

Turning on "Power Mode" will display the results of the calculations alongside the input fields. When "Power Mode" is off, descriptive information sits alongside the input fields for a more informative learning experience.
Savings Information
$
Initial savings is the amount of money currently set aside to invest into a savings or investment account.
%
Expected rate of return is the rate expected on your savings or investment each year. When using the rule of 72, use the rate as a percentage, instead of a decimal as the divisor into 72.

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Rule of 72 Summary

The Rule of 72 is a convenient tool for rough estimates of investment doubling times, especially for interest rates between 6% and 10%. However, its simplicity can be misleading. It assumes constant returns and doesn't account for variable interest rates, compounding frequency, investment-specific nuances, or fees and taxes. While it offers a quick insight, the Rule of 72 is best used as a general guideline rather than a definitive metric. For detailed financial planning, more comprehensive analysis and considerations are essential.