Password Strength Checker
Check how strong a password is, entirely in your browser — nothing is sent anywhere.
Qu’est-ce que Password Strength Checker ?
Password strength estimation is the process of judging how resistant a password is to guessing by approximating its entropy, the number of attempts an attacker would need in a brute-force search. The estimate combines password length with the size of the character set used, then penalizes predictable patterns such as common passwords, keyboard walks, sequential characters, and repeated symbols, which drastically reduce real-world cracking difficulty even when the raw entropy math looks adequate. The result is presented as a strength score alongside a list of specific, actionable weaknesses rather than a simple pass or fail. It complements but cannot replace good practices like unique passwords per account, proper server-side hashing, and multi-factor authentication.
Comment utiliser Password Strength Checker
- Type a password into the field — it's masked by default, click the eye icon to reveal it.
- The strength meter, label, and feedback list update on every keystroke.
- Work through the feedback list (missing character classes, common-password warnings, repeated or sequential patterns) to improve the score.
- Nothing is sent anywhere — check real passwords here with the same confidence as checking them on paper.
Exemples
Common password
Entrée : password
Sortie : Very Weak — matches a known common password
Short but varied
Entrée : Ab3!xQ9
Sortie : Fair — decent variety, but short
Long and varied
Entrée : Tr7$mQ9!xZp2#Lw8
Sortie : Very Strong — no weaknesses detected
Erreurs courantes
- Reusing the same strong password across multiple sites — strength and uniqueness are different properties; a single breach anywhere exposes every account using that password.
- Assuming a long password is automatically strong — predictable patterns (keyboard walks, repeated characters, dictionary words) can make even a 16-character password weak.
- Substituting look-alike characters in common words ("P@ssw0rd") and assuming it defeats modern cracking tools — these substitutions are well-known and checked first.
Pourquoi utiliser cet outil
- Instant feedback on every keystroke, with specific, actionable suggestions instead of just a pass/fail bar.
- Checks against a list of extremely common passwords, not just character variety.
- Detects sequential and repeated-character patterns that pure length/variety scoring misses.
- Runs entirely client-side — genuinely safe to test a real password against, unlike a form that submits it to a server.