Rule of 72 Calculator
Calculate how long it takes for an investment to double using the Rule of 72. Compare doubling times across different interest rates.
Input
Results
Rule of 72: 72 / 6% = 12.00 years
Exact calculation: ln(2) / ln(1 + 6%) = 11.90 years
Asset Growth Chart
Rate Comparison Table
| Rate | Rule of 72 | Exact Value | Difference |
|---|---|---|---|
| 1% | 72.00 years | 69.66 years | +2.34 |
| 2% | 36.00 years | 35.00 years | +1.00 |
| 3% | 24.00 years | 23.45 years | +0.55 |
| 4% | 18.00 years | 17.67 years | +0.33 |
| 5% | 14.40 years | 14.21 years | +0.19 |
| 6% | 12.00 years | 11.90 years | +0.10 |
| 7% | 10.29 years | 10.24 years | +0.04 |
| 8% | 9.00 years | 9.01 years | -0.01 |
| 9% | 8.00 years | 8.04 years | -0.04 |
| 10% | 7.20 years | 7.27 years | -0.07 |
| 12% | 6.00 years | 6.12 years | -0.12 |
| 15% | 4.80 years | 4.96 years | -0.16 |
| 18% | 4.00 years | 4.19 years | -0.19 |
| 20% | 3.60 years | 3.80 years | -0.20 |
| 24% | 3.00 years | 3.22 years | -0.22 |
* The Rule of 72 is an approximation. It is more accurate at lower interest rates.
How to Use
Enter Rate
Enter annual interest rate (%)
Calculate
Doubling time is calculated
View Result
Check approximate and exact results
Features
Instant Calculation
Show result instantly from rate input
Exact Comparison
Compare Rule of 72 estimate with exact compound calculation
Reverse Calculation
Reverse-calculate required rate from target years
FAQ
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