Password Strength Analyser

Free online tool. All processing is client-side. No signup needed.

How to Use the Password Strength Analyser

1. Enter your input values above
2. Results update automatically
3. Copy or download the output

What is a Password Strength Analyser?

A Password Strength Analyzer evaluates the security of your passwords by checking them against multiple criteria: length, character diversity (uppercase, lowercase, numbers, symbols), resistance to dictionary attacks, and absence from known breach databases. In 2026, with AI-powered password cracking becoming faster and retail data breaches exposing billions of credentials, weak passwords remain the #1 cause of account compromises. This tool gives you an instant strength score and specific, actionable recommendations for improvement — all processed entirely in your browser (the password never leaves your device).

How Does It Work?

Type or paste a password. The analyzer evaluates it across multiple dimensions: (1) Entropy — mathematical measure of randomness/predictability, (2) Length — the single most important factor, (3) Character space — size of the character set used, (4) Dictionary resistance — whether it contains common words or patterns, (5) Breach check — SHA-1 hash of the password's prefix is checked against Have I Been Pwned's k-anonymity API (the full password hash is never sent). Final score: Weak, Fair, Good, Strong, or Very Strong.

Formula

Password Entropy = log₂(CharacterSpace^Length) = Length × log₂(CharacterSpace)\n\nCharacter Space Size:\n• Digits only (0-9): 10\n• Lowercase letters: 26\n• Upper + Lower: 52\n• + Digits: 62\n• + Common symbols (!@#$%...): 94\n\nTime to Crack ≈ 2^Entropy ÷ (Guess Rate)\nGuess Rate: ~10⁹/sec (online), ~10¹⁴/sec (offline with GPU)\n\nRecommendation: ≥70 bits entropy for sensitive accounts

Who Uses This Tool?

• Users checking password strength before setting account credentials
• IT security teams evaluating password policy compliance
• Parents helping children create strong gaming and social media passwords
• Developers testing password strength algorithms for applications
• Anyone receiving a 'weak password' warning from a website

Pro Tips

• Length beats complexity. 'horse-battery-staple-correct' (28 chars, ~100 bits) is far stronger than 'P@ssw0rd!' (9 chars, ~40 bits) and easier to remember
• Use a password manager (Bitwarden, 1Password, Apple Passwords) to generate and store unique 16+ character passwords for each site. The best password is one you don't have to remember
• Check haveibeenpwned.com to see if your email or passwords have been in a data breach. If yes, change those passwords immediately
• Never reuse passwords across sites. Credential stuffing attacks (trying leaked username/password combos on other sites) are automated and highly effective

Frequently Asked Questions about Password Strength Analyser

What makes a password strong?

Length is the most important factor. A 16-character random password of mixed case + numbers has ~94 bits of entropy — effectively uncrackable by current technology. Next: uniqueness (never reused), unpredictability (not dictionary words/patterns), and avoidance of personal information (birthdays, pet names).

Should I use a password manager?

Yes. Password managers generate unique, strong passwords for every site and remember them for you. You only need to remember one strong master password. Leading options include Bitwarden (open source, free tier), 1Password, and Apple/iCloud Keychain.

What about passkeys?

Passkeys (FIDO2/WebAuthn) are replacing passwords entirely. They use public-key cryptography: your device holds a private key, the website holds the public key. Passkeys are phishing-resistant and can't be stolen in data breaches. Where available, use passkeys as your primary authentication method.

Free online Password Strength Analyser — no signup, 100% client-side processing. All data stays in your browser.