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Rule of 72 Investment Doubling Calculator

Find the exact years required to double money given an annual return rate.

Tool inputs stay in your browser · optional AI search sends your query

Good to know: The Rule of 72 is a classic financial rule of thumb to quickly estimate the effect of compound interest.

How to use it (step by step)

  1. 1Fill in the boxes: “Annual Expected Return / Interest (%)”. Example numbers are already there so you can see how it works; replace them with yours.
  2. 2The result updates instantly as you type (on a phone it is below the boxes).
  3. 3The bold line is the main answer. Tap Copy next to any value to copy it.

Words to know

Interest
The extra money you pay for borrowing, like a rental fee for using someone else’s money.
Percentage
A part out of 100. 25% of 200 = 50.
Compound interest
Interest that also earns interest over time, so savings (or debt) grow faster and faster.

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