Password Strength Checker

Analyze your password's strength using entropy calculation, charset analysis, and pattern detection. Shows estimated crack time for both online (1,000/sec) and offline fast-hash (10B/sec) attacks. Detects weak patterns: keyboard walks (qwerty, asdf), common passwords, date patterns, repeating characters. Provides specific improvement suggestions.

Entropy Calculation

Entropy (bits) = log2(charset size^password length). Example: 8-character lowercase password: log2(26^8) = 37.6 bits. 12-character mixed case + numbers + symbols: log2(94^12) = 78.4 bits.

Crack Time Estimates

Online attack (1,000 guesses/sec): Time to crack at typical website rate. Offline fast hash (10 billion guesses/sec): Time with dedicated GPU cracker. Shows both to illustrate why offline password databases are dangerous.

Pattern Detection

Keyboard walks: qwerty, asdf, 1qaz, zxcv, qwertyuiop. Common passwords: password, 123456, admin, welcome, letmein. Date patterns: Birth years (1990, 2000), months (jan, feb), dates. Repeating characters: aaaa, 1111, ababab. Sequential numbers: 12345, 54321.

Improvement Suggestions

Increase length to at least 12-16 characters. Add numbers and symbols. Avoid dictionary words. Avoid personal information (name, birthdate). Avoid common patterns. Use passphrase approach for memorable strong passwords.

Security Warning

Password strength checking happens entirely in your browser. Your password is never transmitted anywhere. However, avoid typing your actual passwords into any online tool if you're concerned about security.