Password Strength Analyzer
Check how strong a password really is: entropy, character variety, and estimated time to crack.
About the Password Strength Analyzer
Password strength comes down to one question: how many guesses would an attacker need? This analyzer measures that as entropy (bits of randomness), checks for the patterns that let attackers skip most of the guessing, and estimates how long an offline attack at ten billion guesses per second would take.
The headline lesson from the math: length beats complexity. correct-horse-battery-staple style passphrases of four random words are both stronger and easier to remember than Tr0ub4dor&3. Every character added multiplies the attacker's work; every substitution trick (a to @, o to 0) adds almost nothing because crackers try those automatically.
Everything runs in your browser. The password you type is never transmitted, stored, or logged, which is the only acceptable way for a password checking tool to work. Even so, the safest habit is to test passwords like the one you are considering, not the exact one you will use.
Reach developers and designers who use these tools every day. Privacy-first, no trackers.
Frequently asked questions
Is it safe to type my real password here?
The analysis runs entirely in your browser with no network requests, so nothing leaves your machine. Still, the best practice with any strength checker is to test a password of the same shape rather than the exact final one.
What is entropy?
The number of bits needed to represent all passwords an attacker would have to try. Each added bit doubles the work. Under 40 bits is weak, 60 is reasonable, 80+ is strong against offline attacks.
Why does the tool say my complex password is weak?
Probably length. An 8 character password using every character type has about 52 bits of entropy, crackable in hours with modern hardware. A 16 character lowercase passphrase has 75 bits. Length wins.
What should I actually do about passwords?
Use a password manager, let it generate long random passwords, and turn on two factor authentication for accounts that matter. Memorize only the one passphrase that unlocks the manager, and make that one long.