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Rule of 72
Estimate how long it takes to double your investment
What do you want to calculate?
Typical returns: S&P 500 ~10%, Bonds ~5%, Savings ~2%
About the Rule of 72
The Rule of 72 is a simple formula to estimate the number of years required to double an investment at a given annual rate of return. Divide 72 by the interest rate to get an approximate doubling time. This rule is most accurate for interest rates between 6% and 10%.
About Rule of 72
What is Rule of 72?
Use the Rule of 72 to quickly estimate how many years it takes to double your investment. Simply divide 72 by your expected annual return rate. A fundamental tool for investment planning.
Features & Benefits
- Quick doubling time estimate
- Works with any interest rate
- Compare different rates
- Reverse calculate needed rate
- Educational breakdown
- Exact calculation comparison
Frequently Asked Questions
- How does Rule of 72 work?
- Divide 72 by your annual interest rate. At 8% return, 72÷8=9 years to double your money.
- How accurate is it?
- It's most accurate for rates between 6-10%. We also show the exact calculation for comparison.
- Can I use it for debt?
- Yes, it works for debt too. At 18% credit card rate, debt doubles in about 4 years if unpaid.
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