Rule of 72
9.0 yrs
72 / 8 = 9.0
Exact
9.0 yrs
ln(2) / ln(1 + r)

Quick Reference

1%72.0 years
2%36.0 years
3%24.0 years
4%18.0 years
5%14.4 years
6%12.0 years
7%10.3 years
8%9.0 years
9%8.0 years
10%7.2 years
12%6.0 years
15%4.8 years
18%4.0 years
20%3.6 years
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About Rule of 72

Working with this task no longer requires installing heavy desktop software — Rule of 72 runs entirely in your browser, instantly. Processing runs locally in your browser using modern Web APIs. Nothing is uploaded, nothing is logged, and there is no quota to worry about for casual use. If you find yourself doing this regularly, the rest of the utility suite covers most adjacent tasks with the same approach.

When you'd reach for Rule of 72

  • You're on a public or shared machine and don't want to leave traces of what you're working on.

    Travelers, contractors, anyone working from a friend's computer.

    Nothing is uploaded, nothing persists if you're not signed in.

  • You need to handle a one-off task right before a meeting and don't have time to install anything.

    Anyone working remotely on a borrowed or restricted machine.

    Open the page, get the result, paste it into your doc — under a minute.

  • You're cleaning up a folder of files that accumulated over a project and need to standardize them.

    Designers, writers, and developers wrapping up deliverables.

    Drop each file in, copy the output, move on.

  • You're hitting the daily limit of a paid SaaS and need a backup option for a single quick job.

    Marketers and ops people whose primary tool is metered.

    Stay productive without burning credits.

Frequently asked about Rule of 72

Is Rule of 72 really free?
Yes — Rule of 72 is free for unlimited personal use, with no account required and no watermark on the output.
Can I use Rule of 72 commercially?
Yes. The output of Rule of 72 belongs entirely to you, with no licensing restrictions.
Are my files uploaded to a server when I use Rule of 72?
Rule of 72 processes everything in your browser using local APIs. Your files never leave your device.
What browsers does Rule of 72 support?
Every modern browser released in the last three years: Chrome, Firefox, Safari, Edge, Brave, Opera.
Do I need to create an account to use Rule of 72?
No. Rule of 72 works without any signup. We only ask for an email if you decide to subscribe to a paid plan.

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