Rule of 72 Calculator
Use the Rule of 72 to estimate how long it takes to double your money.
The Rule of 72 is a quick mental math trick: divide 72 by your annual return to estimate years to double. At 7%, your money doubles in about 10.3 years (72/7). At 10%, it doubles in 7.2 years. At 4%, it doubles in 18 years. This calculator shows you both the Rule of 72 estimate and the exact compound interest calculation.
Your Investment Details
Total Value After 20 Years
$40,387
Your money doubles in ~10 years
Total Contributions
$10,000
Interest Earned
$30,387
Interest Share
75%
Contributions vs Interest
Growth Over Time
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