Password Strength Checker Online
Instantly analyze any password. See crack time estimates, entropy score, character analysis, and specific tips to make it stronger.
How the Password Strength Checker Online Works
This password strength checker calculates entropy based on the size of the character set you use and your password length. Entropy measures how unpredictable your password is — the higher the score, the harder it is for any attack to succeed.
Crack time estimates are based on known GPU benchmarks for common attack scenarios: online throttled guessing, offline dictionary attacks, and brute-force at GPU speeds. This gives you a realistic picture, not a theoretical best case.
Your password never leaves your device. Zero server contact. Zero logging.
What this tool does
How to use it
Type your password
Enter any password in the input field. Toggle visibility with the eye icon.
Read the analysis
See your strength grade, entropy score, and exactly what’s making it weak or strong.
Check crack times
The table shows how long it would take different attack methods to break your password.
Generate a better one
Use the built-in generator to create a strong password with your preferred options.
FAQ: Password Strength Checker
Yes. All analysis runs inside your browser using JavaScript. Your password is never sent to any server, never logged, and never stored anywhere. You can verify this by disconnecting from the internet before typing.
Strength is based on entropy in bits, calculated from password length and the size of the character set used (lowercase, uppercase, digits, symbols). Entropy measures unpredictability. Common patterns like keyboard walks or repeated characters reduce the effective score.
Crack times are estimated against different attack speeds: online login attempts (limited by rate throttling), offline dictionary attacks, and GPU brute-force at roughly 10 billion guesses per second. Longer, more complex passwords increase crack time exponentially.
Length is the biggest factor. A 20-character password using only lowercase letters is stronger than an 8-character password with mixed types. Ideally combine length with character variety and avoid dictionary words, common substitutions like @ for a, or predictable patterns.
Yes, if you store it in a password manager. Generated passwords are genuinely random and very strong. If you need something you can memorize, try a passphrase of 4 or more random words instead, which gives high entropy and is easier to recall.