Rule Of 72 Calculator
Get a quick mental-math estimate for growth: enter an annual return to see how many years it takes for money to double — or enter a time span to find the yearly rate you need.
Result
Enter values to see the result.
How to use
- Type an annual return rate — or a number of years — and results update as you type.
- Read the doubling time in the result box, or the yearly rate your goal needs.
- Adjust the numbers to compare different savings or investment scenarios.
Note: The Rule of 72 is a quick estimate — exact compounding gives a slightly different figure, closest near 8 percent.
Tips
- The rule works best for rates between 6 and 10 percent.
- It is an estimate — it assumes steady compounding and ignores taxes and fees.
- For very high rates the doubling time comes out a little too short.