Rule of 144 Calculator
Estimate how many years it takes to quadruple your money at a given return using the Rule of 144 mental shortcut.
How it works
Years to quadruple ≈ 144 ÷ annual return (%) · Exact = ln(4) ÷ ln(1 + rate)
The Rule of 144 estimates how long it takes to grow money fourfold, which is simply two doublings. It works because 144 is twice the 72 used in the doubling rule, and because quadrupling is the same as doubling twice. Divide 144 by your percentage return for a quick answer that needs no calculator, accurate across the range of returns most portfolios earn.
Worked example
At an 8% annual return, the Rule of 144 gives 144 ÷ 8 = 18 years to quadruple. The exact figure, ln(4) ÷ ln(1.08), is about 18.0 years — a near-perfect match.
Frequently asked questions
Why is the constant 144 and not 72?
Quadrupling is two consecutive doublings, and each doubling takes about 72 ÷ rate years. Two of those is 144 ÷ rate, so the same logic that gives the Rule of 72 gives the Rule of 144.
How accurate is it?
For everyday returns it is within a few tenths of a year of the exact logarithmic answer. Accuracy is best in the mid-single-digit to low-double-digit range.
What if I want tripling instead?
Use the Rule of 114 for tripling. The family of rules — 72 for doubling, 114 for tripling, 144 for quadrupling — all follow the 100 × ln(multiple) pattern.
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Educational estimate, not investment advice. Past returns do not predict future results.