Rule of 72 Calculator
Estimate how long it takes an investment to double — or the return needed — using the Rule of 72.
What Is the Rule of 72 Calculator?
The Rule of 72 Calculator uses the classic shortcut — 72 divided by your annual return — to estimate how many years it takes money to double, or the return rate needed to double in a given time. Switch between the two and get an instant estimate. Runs in your browser.
How It Works
Choose From Rate to get the years to double from a return rate, or From Years to get the rate needed to double in a set number of years. The result updates instantly.
When to Use It
Use it for quick investing mental math, comparing returns, or teaching how compounding doubles money over time.
Frequently Asked Questions
- How accurate is the Rule of 72?
- It's a close approximation, most accurate for returns around 6–10%. For exact figures, use the Compound Interest Calculator.
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