免费72法则计算器
利用72法则快速估算投资翻倍所需时间，或达到翻倍目标所需的利率。
%
Years to Double
9.0
Exact Years (ln2/r)9.01
Years to Double vs Annual Interest Rate
公式
The Rule of 72
Years to Double ≈ 72 / Interest Rate
This is an approximation. The exact formula is:
Years = ln(2) / ln(1 + r)
The Rule of 72 is most accurate for rates between 6% and 10%.
计算示例
Your investment earns 8% annually.
- 01Rule of 72: 72 / 8 = 9.0 years
- 02Exact: ln(2) / ln(1.08) = 0.6931 / 0.07696 = 9.01 years
常见问题
Why is it called the Rule of 72?
72 is used because it is easily divisible by many common interest rates (1, 2, 3, 4, 6, 8, 9, 12) and provides a close approximation.
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