Rule of 72 Calculator
The Rule of 72 is a quick way to estimate how long an investment takes to double at a given rate of return.
Your details
Years to double (Rule of 72)
9
- Exact years
- 9.01
Years to double (Rule of 72)9
Formula
Years to double ≈ 72 ÷ rate. The exact value is ln(2) ÷ ln(1 + rate).
Sources & methodology
- •U.S. SEC — compound interest — SEC
Last updated: 2026-07-20
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