Password & Security
Password Strength Checker
Estimate password entropy and time-to-crack in real time.
Enter a password above to see its strength and estimated crack time.
Password & Security
Estimate password entropy and time-to-crack in real time.
Enter a password above to see its strength and estimated crack time.
A password strength checker is a security utility that measures password robustness by scoring factors like character count, uppercase/lowercase/number/symbol inclusion, dictionary word detection, and common substitution patterns. The result is a strength rating (weak, fair, good, strong, very strong) and specific feedback on how to improve it.
The checker analyzes your password character-by-character, calculating entropy (the theoretical number of guesses needed to crack it), checking against known weak passwords and keyboard patterns, and identifying reused character types. It then combines these signals into a single strength score: longer passwords with mixed character types score higher, while short, repetitive, or dictionary-based passwords score lower.
| Input | Result | Notes |
|---|---|---|
| password123 | Weak (Entropy: 19 bits) | Common dictionary word + simple number sequence; cracks in minutes |
| Tr0pic@lS1nset2024 | Strong (Entropy: 68 bits) | 18 characters, mixed case, numbers, symbols, no dictionary words; ~4,000+ years to crack |
| xK$9pL2mQ@wR | Strong (Entropy: 72 bits) | 12 random characters, high entropy, unpredictable; impractical to crack |
Entropy is the number of bits of randomness in your password. A 50-bit entropy password requires 2^50 guesses on average to crack; a 72-bit password requires 2^72 guesses, which is impractical even with fast computers.
It's based on the word 'password' (dictionary), uses predictable substitutions (@ for 'a', 0 for 'o'), and is only 10 characters. AI-powered crackers and rule-based attacks exploit these patterns faster than brute force.
No. The checker runs entirely in your browser; your password never leaves your device and is never sent to FreeTooz servers. You can disconnect from the internet and the tool still works.
A strong password (60+ bits entropy, 12+ mixed characters) would take a modern computer billions of years to crack by brute force. Real attacks succeed faster via phishing, reuse, or poor account security—so use unique passwords and two-factor authentication.
No. Use a unique strong password for each account. If one site is breached, attackers can test that password on others. Use a password manager (1Password, Bitwarden, KeePass) to generate and store different passwords securely.
Length is the biggest factor (each extra character multiplies entropy by ~5). After 12+ characters, adding symbols, uppercase, numbers, and lowercase in random combinations provides diminishing returns but still helps against specialized attacks.