This tool checks your password locally in your browser against length, character variety, common patterns, and known leaked passwords, then estimates how long it would take to crack. Nothing you type here is ever sent, logged, or stored.
Security Checklist
- Minimum 8 characters
- Minimum 12 characters
- Uppercase letter
- Lowercase letter
- Number
- Special character
- No repeated characters
- No sequential numbers
- No sequential letters
- No common keyboard patterns
- No dictionary words
- No common/leaked passwords
- No personal information detected
Estimated Crack Time
Entropy & Complexity
Improvement Suggestions
- Enter a password to receive tailored recommendations.
Privacy First
Your password is analyzed entirely inside your browser. Nothing is transmitted, stored, or logged on our servers — not even when checking it against common keyboard patterns or leaked-password lists, since those checks all run locally too.
Best Password Practices
- Use at least 12–16 characters — length matters more than complexity alone.
- Use a different, unique password for every account.
- Avoid dictionary words, names, and predictable substitutions like "@" for "a".
- Avoid keyboard patterns (e.g. "qwerty") and sequential characters (e.g. "abc123").
- Enable Multi-Factor Authentication (MFA) wherever it's available.
- Store passwords in a trusted password manager instead of memorizing or reusing them.
- Change a password immediately if you suspect it's been exposed or leaked.
- Never share your passwords over email, chat, or phone.
Frequently Asked Questions
Is my password ever sent to a server?
No. Every check — length, character variety, entropy, pattern detection, and the leaked-password comparison — runs locally in your browser using JavaScript. Nothing is transmitted, logged, or stored.
How is the strength score calculated?
The strength meter uses zxcvbn, a widely used open-source password-strength estimation library, which models realistic guessing strategies (dictionaries, patterns, keyboard walks, and common substitutions) rather than a simple character-type count. The Security Checklist below it shows the individual rules your password passes or fails.
Why did my password get flagged even though it's long?
Length alone doesn't guarantee strength. Long passwords built from dictionary words, names, or predictable patterns can still be guessed quickly by modern cracking tools — that's why entropy, pattern detection, and leaked-password matching are checked too.
What is a strong password?
A strong password is long, random, and unique — ideally generated rather than composed by hand — and combines uppercase letters, lowercase letters, numbers, and symbols without forming a recognizable word or pattern.
Is this tool free?
Yes. FirewallFlow provides this password strength checker completely free.