Doubling Time Calculator
Estimate the time for an investment to double.
Runs locally in your browser — your numbers never leave this pageTry: Annual rate=7 → 7.00%, 10.3 years
How to use
Doubling time answers “how many years until this doubles?” using the rule of 72, a fast approximation that needs no calculator memory.
Formula
Doubling time ≈ 72 / r
FAQ
Does it work for anything growing?
Yes — populations, prices, or any steady percentage growth, not just money.
Why not just use CAGR?
You can, but the rule of 72 gives an instant estimate without exponents.
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