Doubling Time Calculator
See how many periods it takes to double or triple at a compound growth rate.
Result
How to use
- Enter your values in the fields above.
- Press Calculate to see your result instantly.
- Use the Share button to copy a link to your result.
About this calculator
This calculator finds how many periods it takes an amount to double or triple at a given compound growth rate, using t = ln(2)/ln(1+r) for doubling and t = ln(3)/ln(1+r) for tripling, and also shows the quick mental-math shortcut, the Rule of 72 (72 ÷ rate ≈ years to double).
Investors and savers use it to see how long it takes a portfolio, savings account, or any compounding quantity to grow, and to compare the real math against the Rule of 72 approximation people often quote from memory.
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