How it works
The rule of 72 divides 72 by the rate for a quick estimate; the exact figure uses logarithms and is shown next to it.
Example
At 6% the rule gives 12.0 years, while the exact doubling time is about 11.9 years.
This tool is for estimation and education, not financial, tax, or legal advice.
Frequently asked questions
Are the results exact lender quotes?
No. Results are estimates from the values entered and exclude terms or charges not shown.
Does the calculator send my numbers anywhere?
No. The calculation runs locally in your browser.
How should I use the result?
Compare scenarios, then verify important figures against a lender disclosure or account statement.
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