Password Strength Checker

Test password strength with entropy analysis and crack-time estimates — locally.

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About the Password Strength Checker

Type a password to see its entropy, character variety analysis, common-pattern warnings (dictionary words, sequences, repeats, years) and estimated crack times at several attacker speeds. Checking is 100% local — the password never leaves the page.

Most "check your password" sites transmit what you type; this one demonstrably cannot, as no network request is made.

How to use the Password Strength Checker

  1. Type or paste a password (it stays on your device).
  2. Review entropy bits, variety checks and pattern warnings.
  3. Read estimated crack times for online and offline attacks.

Common uses

Auditing your important passwords Teaching password hygiene Testing password policy candidates

Frequently asked questions

Is it safe to type a real password here?
Yes — analysis is local JavaScript with zero network activity. Still, best practice is testing similar patterns rather than exact credentials.
What makes a password weak?
Short length, single character class, dictionary words, keyboard sequences and predictable substitutions (p@ssw0rd).
What is entropy?
A measure of unpredictability in bits — each added bit doubles the guesses an attacker needs.

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