Runs in your browser · Last updated 7 September 2026
Free Password Strength Checker
Free password strength checker. Entropy from character-class pool, common-password floor, sequences — not a toy meter. Browser tool — nothing is uploaded.
Entropy is length × log2(character-class pool), then penalties for common passwords, sequences, and repeats. Offline crack time assumes 10¹⁰ guesses/s (a GPU hash), not a website login throttle. This is not zxcvbn and not a password generator.
Score
0 · very weak
Entropy
0.0 bits
Charset size
1
Length
0
Offline crack (1e10/s)
instant
How to use this tool
- Type or paste a candidate in the field (it is masked).
- Read score, bits, and flags. A long mixed passphrase beats a short mixed token.
Worked example
password1 is score 0 — common list, ~12 bits. W3st-l@ke-maple-9f!r is a 20-character mixed string: four classes, no sequence, well above 56 bits on this meter. Hash checksums are a different job (SHA-256 / HMAC pages).
Frequently asked questions
- Is this zxcvbn?
- No. It is a local entropy estimate: character-class pool × length, then penalties for a common-password list, keyboard/alpha sequences, and repeats. zxcvbn’s full dictionary and l33t graph are not shipped.
- Why is password1 very weak?
- It is on the common-password list. A trailing digit does not save a leaked password. Entropy is floored so the meter cannot call it strong.
- What is the crack-time assumption?
- 10¹⁰ guesses per second — a GPU against a fast hash, not an online form with lockouts. Real attackers may be slower (Argon2) or faster (unsalted SHA-1).
- Do you store the password?
- No. The field stays in this tab. Prefer a password manager; this page does not generate secrets.