Rule of 72 Calculator
The Rule of 72 is a fast mental shortcut for how long it takes money to double at a given compound rate: divide 72 by the annual rate and you get the number of years. Enter your expected annual interest or return rate and this calculator gives you the doubling time instantly, and it also works the reverse way, showing what rate you would need to double your money in a target number of years. It is an approximation, most accurate for rates in the middle single digits, but it is remarkably close and needs no complex math, which is why investors use it to sanity-check returns on the fly. Try different rates to feel how much faster a few extra percent compounds. It all runs in your browser.
How to use Rule of 72 Calculator
- Enter your annual return rate.
- Read the estimated years to double.
- Or enter a target and read the rate needed.
Frequently asked questions
How does the Rule of 72 work?
You divide 72 by the annual return rate to estimate the years it takes for money to double at that rate.
How accurate is it?
It is a quick approximation that is closest for rates around 6 to 10 percent. For exact figures use a compound interest calculation.
Can it find the rate to double by a target?
Yes. Enter a target number of years and it divides 72 by that to estimate the return rate you would need.
What is Rule of 72 Calculator?
The Rule of 72 is a fast mental shortcut for how long it takes money to double at a given compound rate: divide 72 by the annual rate and you get the number of years. Enter your expected annual interest or return rate and this calculator gives you the doubling time instantly, and it also works the reverse way, showing what rate you would need to double your money in a target number of years.
Is Rule of 72 Calculator free to use?
Yes. Rule of 72 Calculator is completely free, with no sign-up and no usage limits.
Does Rule of 72 Calculator work in a web browser?
Yes. Rule of 72 Calculator runs in any modern web browser. There is nothing to download or install.
Is my data private with Rule of 72 Calculator?
Yes. Rule of 72 Calculator runs entirely on your device in your browser, so nothing you enter is uploaded to a server.
Badge
Link this tool from a README, doc or site. The badge links back to this page.
[](https://yourhack.ai/rule-of-72-calculator)