72er-Regel-Rechner — Formel
## 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%.
**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%.
Lösungsbeispiel
Your investment earns 8% annually.
- Rule of 72: 72 / 8 = 9.0 years
- Exact: ln(2) / ln(1.08) = 0.6931 / 0.07696 = 9.01 years