Growth estimate

🌅 Rule of 72 Calculator

Estimate how long an investment may take to double—or the annual return needed to reach a doubling goal.

Rate to doubling time

Enter an estimated annual return rate.

Estimated time to double 9 years 72 ÷ annual return rate

Doubling goal to rate

Enter the desired number of years.

Estimated annual return needed 7.2% per year 72 ÷ desired doubling time

What is the Rule of 72?

The Rule of 72 is a quick way to estimate how long an investment may take to double when it earns a steady, positive annual return.

Estimate doubling time Years ≈ 72 ÷ annual rate
Estimate required return Annual rate ≈ 72 ÷ years

This is an approximation rather than a prediction. It assumes steady compounding and does not include additional deposits or withdrawals.

For educational purposes only. Results are estimates and do not include taxes, fees, inflation, contributions, withdrawals, or changing rates of return.