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Calcimator

Rule of 72 Deep Dive Calculator

Explore the Rule of 72 and beyond — calculate exact doubling, tripling, and 10x times adjusted for inflation and fees.

Inputs

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Results

Rule of 72 Estimate (years)

9

Exact Doubling Time (years)9.01
Rule of 69.3 Estimate (years)8.66
Real Doubling Time (years)15.75
Tripling Time (years)14.27
10x Time (years)29.92
Value at Doubling ($)$20,000
Net Effective Rate (%)4.5%
Real Value At Doubling20,000
How to Use This Calculator
  1. Enter your expected annual return rate (e.g., 8% for a stock index fund).
  2. Add an optional initial investment to see the actual dollar value when it doubles.
  3. Enter your expected inflation rate to see the real (inflation-adjusted) doubling time.
  4. Set annual fees or expense ratios to see how they reduce your effective doubling time.
  5. Review the Rule of 72 estimate, exact doubling time, tripling time, and 10x time.
  6. Compare the net effective rate after fees and inflation to your gross return.
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