Password Strength Checker
Check how strong your password is with comprehensive security analysis. Get entropy calculation, estimated crack time (at 10 billion guesses/sec), and 8 security checks covering length, complexity, common passwords, repeating characters, and sequential patterns. All analysis runs in your browser — nothing is sent to any server.
Password Strength Checker
How to Use Password Strength Checker
- 1Enter a password in the input field
- 2View the strength score and crack time estimate
- 3Check which security criteria pass or fail
- 4Improve your password until all checks pass
Frequently Asked Questions
How is password strength calculated?▾
We measure 8 factors: length (12+ chars), uppercase/lowercase mix, numbers, special characters, absence of common passwords, no repeating characters, and no sequential patterns. We also calculate entropy (bits of randomness) and estimate crack time assuming 10 billion guesses per second.
Is my password sent to a server?▾
No — all analysis happens entirely in your browser using JavaScript. Your password never leaves your device. You can verify this by checking the network tab in your browser's developer tools.
What makes a strong password?▾
A strong password has 12+ characters, mixes upper/lowercase letters with numbers and symbols, avoids dictionary words and common patterns (abc, 123), and is unique per account. Consider using a passphrase: 4+ random words like 'correct-horse-battery-staple'.
About Password Strength Checker
Check how strong your password is with comprehensive security analysis. Get entropy calculation, estimated crack time (at 10 billion guesses/sec), and 8 security checks covering length, complexity, common passwords, repeating characters, and sequential patterns. All analysis runs in your browser — nothing is sent to any server.
NexTool's Password Strength Checker is completely free to use with no sign-up required. Your data is processed directly in your browser and never sent to our servers, ensuring complete privacy and instant results.
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