Calculateur d'Entropie du Mot de Passe
Calculate password entropy bits and estimate crack time
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Enter a password above to see its entropy and crack time estimates.
À propos de cet outil
Password entropy measures, in bits, how unpredictable a password is based on its length and character variety - higher entropy means exponentially more possible combinations an attacker would need to try. This tool calculates a password's entropy and estimates roughly how long it would take to crack by brute force.
Bien sécuriser un compte
- 1Générer un mot de passeLong et aléatoire bat malin.Ouvrir
- 2Vérifier sa robustesseVoyez combien de temps il faudrait pour le craquer.Ouvrir
- 3Mesurer l'entropieLes maths derrière son degré réel de devinabilité.Vous êtes ici
Comment utiliser cet outil
- Enter test password patternUse representative password style to assess practical strength.
- Calculate entropy scoreMeasure effective unpredictability and estimated brute-force complexity.
- Review crack-time estimateInterpret model assumptions and identify weak structure patterns.
- Improve password strategyIncrease length/randomness or switch to generated passphrases/password manager.
Pourquoi l’utiliser
- Quantifies password strength beyond vague “strong/weak” labels.
- Highlights real impact of length and randomness choices.
- Useful for policy education and user-security training.
- Supports better password standard decisions.
Usages courants
- Evaluating enterprise password policy quality.
- Teaching users why longer random credentials matter.
- Comparing passphrase vs symbol-heavy short passwords.
- Auditing generated credentials before account provisioning.
Conseils pour de meilleurs résultats
- Prioritize longer length over cosmetic symbol substitutions.
- Use unique passwords per service with a password manager.
- Avoid dictionary patterns and predictable keyboard sequences.
- Treat crack-time estimates as guidance, not guaranteed safety.
Erreurs à éviter
- Believing complexity rules alone guarantee high entropy.
- Reusing high-entropy password across multiple accounts.
- Relying on memorable phrases with common word patterns.
- Ignoring MFA even with strong password entropy scores.
Questions fréquentes
Higher is better - many security guidelines suggest aiming for at least 60-80 bits of entropy for important accounts, though the practical threshold depends on what you're protecting and against what kind of attacker.
It's based on the total number of possible combinations (determined by entropy) divided by an assumed number of guesses an attacker could attempt per second - actual crack time in the real world also depends heavily on the specific system's security measures beyond just the password itself (like rate limiting).
Length is a major factor, but entropy also depends on unpredictability - a long but predictable password (like "passwordpasswordpassword") has much lower real-world entropy than its length alone would suggest, since attackers can exploit the pattern.
Yes. Password Entropy is free for normal use with no account required, and ToolBox does not add a watermark to your result.
Most tools in this category run in your browser so the file stays on your device. If a tool needs a temporary server job, files are handled for that job only and are not kept as a lasting archive.
No install needed. Open Password Entropy in your browser, add your file or paste your input, then download or copy the result.
Yes on modern mobile browsers. For large files, a desktop browser is usually faster and more reliable.
Try a different quality or format setting, use a smaller input, or open a related tool (for example compress before convert). Keep a copy of the original file before replacing it.
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