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Password Strength Tester

Review a password example with a local length-and-pattern heuristic and upper-bound search-space illustrations. Avoid entering a live credential.

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🔒 The tester logic runs locally. Avoid entering a password currently in use.

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About This Tool

What it does

Applies a local length-and-pattern heuristic and displays upper-bound search-space and offline brute-force illustrations. It cannot prove that a password is safe or unique.

Who it's for

Anyone who wants to check if their existing passwords are strong enough before reusing them or continuing to use them. Used in the UK, US, Australia, Canada, Singapore, UAE and worldwide.

Your privacy

The tester’s own calculation runs in this page and does not submit the entered value. That does not remove risks from compromised devices or extensions, so use a similar example rather than a live credential.

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Method, limits and privacy

This tool does not send the entered value from its own script, but it is still safer not to type a live credential. Length is counted in Unicode code points. The search-space and time values are upper-bound illustrations, not measured entropy or guaranteed crack times.

Sources reviewed 23 June 2026: NIST SP 800-63B

Frequently Asked Questions

No. It is a transparent local heuristic that checks length and a small set of obvious patterns. It cannot test reuse, breach exposure, personal information, phishing resistance or the receiving service’s controls.
It is length multiplied by the logarithm of an estimated character pool. Human-created passwords are rarely uniform random samples, so the real guessing difficulty can be much lower.
It divides half of the upper-bound search space by 10 billion guesses per second. This deliberately simplified ceiling is not a forecast; attack speeds and smarter guessing strategies vary.
The page analyses text locally, but that does not remove risks from compromised devices, malicious extensions, screen capture or clipboard tools. Test a similar example rather than a password currently in use.

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