12/10/2024
The beauty of the Rule of 72 lies in its simplicity—it transforms complex financial concepts into decisions anyone can understand.
The rule becomes particularly useful when comparing different investment options. Consider these common scenarios:
A savings account paying 1% interest: 72 years to double (72 ÷ 1 = 72)
A corporate bond yielding 4%: 18 years to double (72 ÷ 4 = 18)
A stock portfolio averaging 8%: nine years to double (72 ÷ 8 = 9)
For returns under 10%, the Rule of 72 provides remarkably accurate estimates for expected annual returns. However, its precision decreases with very high or very low rates. A companion formula, the Rule of 69, offers more accurate results for such cases but is less practical for quick mental math for most.
Here are other rates and how long it would take for your initial investment to double:
