Rule of 72 Calculator
Approximate the doubling time of an investment from its interest rate.
Educational estimate, not financial advice.
Examples
- 6% ⇒ 12 years
- 8% ⇒ 9 years
- 12% ⇒ 6 years
FAQ
Why use 72?
72 is a convenient number divisible by many rates.
Is the rule exact?
No, it's an approximation for quick mental math.
Can I enter decimals?
Yes, use any positive rate.
Additional Information
- Result unit: years