Rule of 72 Calculator
Estimate years for an investment to double at a given return rate.
Frequently asked questions
What does the Rule of 72 Calculator do?
Estimate years for an investment to double at a given return rate. Enter your values and get an instant estimate in your browser — free, with no signup.
Is the Rule of 72 Calculator free to use?
Yes. OpenCalcy calculators are free to use, work on mobile, and keep favorites privately in your browser.
How is the Rule of 72 Calculator calculated?
It uses this formula: Years ≈ 72 / rate%