2ī¸âŖ Rule of 72 Calculator
Calculate years to double (rule of 72), years to double (exact) instantly from interest rate % per year.
Results are estimates for information only and are not financial advice. See our disclaimer.
How to use the Rule of 72 Calculator
- Enter Interest rate % per year.
- The result updates instantly as you type.
- Copy or note down your result.
How it works
Formulas: Years to double (rule of 72) = 72/[Interest rate % per year]; Years to double (exact) = log(2)/log(1+[Interest rate % per year]/100).
Example
Using the default values (Interest rate % per year: 8):
Years to double (rule of 72)9 years
Years to double (exact)9.0065 years
FAQ
Is the Rule of 72 Calculator free to use?
Yes. It is free, needs no signup and has no usage limits.
Is my data safe?
Yes. Everything is calculated in your browser, so what you type or upload is never sent to a server.
Can I use it on my phone?
Yes. KsWebProduction is built mobile-first and works in any modern browser.