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Money Doubling Calculator (Rule of 72)

See how many years it takes to double your money.

Last updated: 13 Aug 2026

Quick answer

The Rule of 72 estimates doubling time: years ≈ 72 ÷ annual return. For example, at 8% your money doubles in about 9 years. Enter your expected return above.

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The Rule of 72 is a quick way to estimate how long an investment takes to double: years ≈ 72 ÷ annual return rate.

How to use the Rule of 72

  1. 1 Enter the expected annual return rate.
  2. 2 We divide 72 by the rate.
  3. 3 You see the approximate years to double.

Frequently asked questions

What is the Rule of 72?
A shortcut: divide 72 by the annual return to estimate the years for money to double.
How accurate is it?
It is a close approximation for typical rates (6–10%); exact doubling uses logarithms.
What return doubles money in 6 years?
About 12% (72 ÷ 12 = 6).

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