Investing
Exact doubling time
The precise time to double from the compound growth equation.
The Formula
Years = ln(2) / ln(1 + rate)
The precise time to double from the compound growth equation.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| ln2 | Natural log of two | number | Constant approximately 0.693. |
What Each Symbol Means
ln2number
Natural log of two
Constant approximately 0.693.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate the rule of 72 page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate The Rule Of 72, filed under Finance. Every number the guide produces comes from substituting into this one line.