Password Strength Analyzer

Check password strength free online using real entropy analysis. Detects common patterns, dictionary words, and keyboard sequences, not just character count rules.

Enter a password to analyze

Browser only -- your password is never sent anywhere.

How to Use This Tool

Type a passwordEnter any password you're considering, real or test

Read the entropy scoreSee actual unpredictability, not just a character checklist

Fix flagged issuesAddress detected patterns like dictionary words or keyboard walks

Most Password Strength Meters Reward the Wrong Things

"Tr0ub4dor&3" famously satirized in an XKCD comic scores high on most simple meters -- it has uppercase, numbers, and a symbol. It is also a known weak pattern because the substitutions (o to 0, a to 4) are in every password-cracking dictionary built since the 2000s. This tool scores passwords the way real attackers think: dictionary checks, pattern detection, and entropy estimation, not a checklist of character types.

Each character type box you tick adds very little real protection if the overall structure is still predictable. A genuinely strong password resists both dictionary attacks and pattern-based guessing, which is what this analyzer actually measures.

What Real Cracking Tools Check First

Password crackers do not try random characters first -- they try dictionary words, common substitutions, keyboard sequences (qwerty, asdf), repeated characters, and known leaked passwords, because these patterns cover the vast majority of real-world passwords. Only after exhausting pattern-based guesses do they fall back to brute force, which is why pattern detection matters more than raw length for realistic security.

Entropy as the Honest Measurement

Entropy estimates how many guesses an attacker would realistically need, accounting for the patterns actually present. A 12-character password built from a real word and simple substitution might have less effective entropy than an 8-character truly random string, even though it looks longer and more complex on the surface.

Frequently Asked Questions

Simple rule-based checkers reward 'Password1!' with a high score because it has uppercase, a number, and a symbol, even though it's one of the most commonly guessed passwords. This tool uses pattern detection inspired by the open-source zxcvbn approach (originally built at Dropbox) -- it checks for dictionary words, keyboard walks, repeated characters, and common substitutions, then estimates actual guessing difficulty rather than just counting character types.

Entropy measures how unpredictable a password actually is, accounting for patterns a simple length count misses. 'aaaaaaaaaa' is 10 characters but has almost no entropy since it's trivially guessable. 'xK9$mQ2vL!' might be shorter but has far higher entropy because there's no pattern to exploit.

Yes. Sequential keyboard patterns are one of the most common password weaknesses and one of the first things real password crackers check for. This tool flags adjacent-key sequences specifically, not just dictionary words.

Detected. Attackers' cracking tools have included these substitution patterns (a→@, o→0, e→3) in their dictionaries for over a decade, so 'P@ssw0rd' offers very little more protection than 'password' itself despite looking more complex.

No. The entire analysis runs in your browser using JavaScript. Your password is never transmitted, logged, or stored -- which matters, since pasting a real password into any tool that does send it elsewhere would itself be a security risk.