How long until your investment triples? This tripling time calculator tells you how many periods it takes for a quantity to triple given a constant growth rate.
Tripling Time Calculator
Using the tripling time calculator
Enter your expected Rate per period as a percentage. The calculator instantly shows how many periods it takes to triple.
The period can be whatever timeframe matches your rate: if you enter an annual return, you get years; monthly return, months.
The tripling time formula
The formula for tripling time is:
Where r is the rate per period as a decimal (e.g., 10% = 0.10).
Example: tripling at 10%
How long to triple an investment growing at 10% per year?
The Rule of 115
Just like the Rule of 72 for doubling, there's a Rule of 115 for tripling:
At 10%, money triples in roughly 115 / 10 = 11.5 years. At 8%, about 115 / 8 ≈ 14.4 years.
Why 115? Because ln(3) × 100 ≈ 109.9, and 115 is a rounder number that still gives reasonable estimates.
Tripling vs. doubling
Tripling takes about 1.58× as long as doubling at the same rate – that's because ln(3) / ln(2) ≈ 1.585. So if doubling takes 10 years, tripling takes about 15.8 years.
