Home › Utility & Security Tools › Password Strength Checker
Check how strong any password is — entropy estimate, crack time, character set analysis, and specific suggestions for making it stronger.
Password Checker · secure calculations performed offline inside your browser
Type any password into the field. The strength analysis runs immediately — nothing is stored or transmitted.
See the strength score (Weak / Fair / Strong / Very Strong), entropy in bits, estimated crack time under different attack scenarios, and which character set categories are present.
Specific suggestions tell you what to add to improve the strength — more length, a missing character type, or avoiding common patterns.
Length is the most important factor — every additional character multiplies the search space exponentially. Character diversity (mixing uppercase, lowercase, numbers, and symbols) expands the character set, further multiplying the possibilities. Avoiding dictionary words, keyboard patterns (qwerty, 12345), and common substitutions (p@ssw0rd) is also important, as attackers prioritise these patterns in their wordlists.
Entropy measures password randomness in bits. A password with 40 bits of entropy has 2^40 possible values. Higher entropy means more guesses required for brute-force — each additional bit doubles the search space. A good general-purpose password has 60+ bits of entropy; a high-security password should have 80+ bits.
Crack time estimates are based on assumed attack speeds for different attack methods: online attacks (throttled by the server, typically 10–100 guesses/second), offline attacks against an unsalted hash (millions to billions of guesses/second depending on the algorithm), and GPU-accelerated attacks against common hash functions. These are estimates — actual difficulty depends on the attacker’s resources and the hash algorithm used.
No. All analysis runs entirely in your browser. Your password never leaves your device and is not logged or stored anywhere.
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Password strength is often misjudged — people believe “complex” short passwords are strong while “long but simple” passwords are weak, when the opposite is typically true for brute-force resistance. This checker gives you the numbers: entropy in bits, estimated crack time under realistic attack scenarios, and specific feedback on what’s missing. It’s useful for checking passwords you’re considering using, testing whether a generated password meets your security requirements, and understanding what makes password length and diversity matter mathematically.
All analysis runs in your browser. Passwords are never transmitted, stored, or logged anywhere.
