Summary
A quick compounding approximation at a constant annual rate.
Calculation details
Divides 72 by the annual percentage rate. It is an approximation, not an exact compound solution.
Formula
Years to double ≈ 72 / annual rate (%).
Worked example
8% annual return
Doubling takes about 9 years.
How it works
Enter a positive annual rate percentage.
Frequently asked questions
What does this Rule of 72 estimate estimate include?
It approximates doubling time as 72 divided by the annual percentage rate.
When is this Rule of 72 estimate most useful?
When you need a quick teaching estimate of doubling time at a steady compound return.
Are displayed values rounded?
The formula keeps full numeric precision. Values are rounded only when formatted for display.
Can actual results differ?
Yes. It is an approximation; exact compounding and irregular returns differ.