How to Use the Rule of 72 to Estimate Doubling Time
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Investments • Jun 2026How to Use the Rule of 72 to Estimate Doubling Time
Calculate how many years it takes for an investment to double in value using mental math.
The Mental Shortcut for Investors
Divide 72 by your annual interest rate to find the approximate doubling timeframe. For example, a 8% return doubles capital in roughly 9 years (72 / 8 = 9).