Rule of 72 Calculator
💷 Money & growth. Use the Rule of 72 formula to find years to double, rate: pick the value you want, type the others, and the answer updates as you go.
A quick estimate of how many years it takes money to double at r% a year.
Pick the ○ next to the value you want to find, fill in the others, and it solves as you type.
What each letter means
| Quantity | Unit |
|---|---|
| Years to double | years |
| Rate | % per year |
Worked example
Find the years to double when Rate = 6 % per year.
Using t ≈ 72/r: Years to double = 12 years.
Frequently asked questions
What is the formula for Rule of 72?
t ≈ 72/r. A quick estimate of how many years it takes money to double at r% a year.
What do the letters stand for, and what units are used?
Years to double in years, Rate in % per year.
How do you calculate years to double?
Put the values into t ≈ 72/r. For example, with Rate = 6 % per year, years to double = 12 years.
Can I solve for a different value?
Yes. In the calculator above, pick the circle next to any value (years to double, rate) and fill in the others: it rearranges the formula for you.
