Something wrong with this tool?
About Password Strength Checker Online
This tool analyses a password and estimates how strong it is against common attacks. It checks length, character variety, dictionary words, common patterns (123, qwerty), keyboard sequences, and known breach data, then reports a strength score and estimated time to crack with current hardware.
Use it to test passwords before adopting them — pick something the tool rates as "strong" or "very strong", not just one you'd find acceptable yourself. Many passwords that feel safe (Password123!, Tr0ub4dor) score poorly because the patterns are well-known.
All analysis happens in your browser. Nothing is sent to a server. Password lookups against breach data use k-anonymity (only the first 5 hash characters are sent), so no full hash or password leaves your machine.
How to use this tool
How to estimate the strength of a candidate password
Enter the password
Drop the candidate into the "Password" field. The check is done locally in your browser — nothing is sent to the server, but treat the form like a real one anyway (don't paste a production password into a tool you don't trust).
Press Run
Result returns `score` (0–4, higher is stronger) and `feedback` (a short hint string like "add more characters" or "avoid common patterns"). The score is heuristic — based on character classes, length, and dictionary hits, similar to zxcvbn-style estimators.
What the score really means
0–1 = trivial to brute-force online (less than a million guesses). 2 = guessable with online attack against unthrottled API. 3 = safe against most online attacks. 4 = safe against offline attacks too. For service logins, aim for 3+.
Length beats complexity
A 20-character lowercase pass-phrase scores higher than an 8-character `Pa$$w0rd!` because length-based entropy compounds faster than punctuation tricks. The XKCD-style "correct horse battery staple" pattern reaches 4 easily.