How strength is calculated
The score (0-100) combines: length, presence of lowercase/uppercase/digits/symbols, and penalties for known weak patterns — commonly used passwords (like "123456" or "password"), predictable sequences, and repeated characters.
Privacy by design
Unlike online checkers that send your password to a server (even hashed), this tool runs entirely as JavaScript in your browser. The analysis function's code contains no network calls — you can verify this by inspecting the publicly served tools.js file on this site.
What to do about weak passwords
Prefer long passwords (12+ characters), unique per service, generated by a password manager — see also our random password generator.
Frequently asked questions
Is my password sent to any server for this check?
No. All analysis happens locally in your browser via JavaScript — there's no network call in the function, which you can verify in the site's public source code.
Does a high score guarantee the password is unbreakable?
There's no absolute guarantee, but a high score indicates the absence of the most common issues (short, predictable, repetitive) that make a password easy to guess or crack.
How is this different from the site's password generator?
The generator creates a brand new random password; this checker analyzes a password you already have or are considering using.