How it works
Approximate doubling years = 72 / annual percentage growth rate. Compare mentally with logarithmic doubling for a constant rate.
Input definitions
- Annual growth rate (%)
- Enter the value in the labeled unit.
A worked example
- Annual growth rate (%)
- 8
Assumptions & limits
Planning model using the rates, cash flows and periods entered. Examples are illustrative, not market quotes or personalised financial advice. Taxes, inflation and transaction costs are excluded unless explicitly entered.
Sources & review
Maintained by AnsRio. Methods and examples use automated checks; this does not imply independent professional certification.
Method updated 2026-10-18. Content checked against the stated method and examples. Our verification approach.
Common questions
Is the rule of 72 an exact forecast?
No. It is an approximation for positive constant compound growth. Variable returns, fees and inflation change the outcome.
How does Rule of 72 comparison work?
Approximate doubling years = 72 / annual percentage growth rate. Compare mentally with logarithmic doubling for a constant rate.
What should I check before using Rule of 72 comparison?
Planning model using the rates, cash flows and periods entered. Examples are illustrative, not market quotes or personalised financial advice. Taxes, inflation and transaction costs are excluded unless explicitly entered.