Password Strength Checker

Password Security Best Practices

• Use 16+ characters — length is the most important factor
• Mix uppercase, lowercase, numbers, and symbols
• Use a passphrase of 4+ random words (e.g., correct-horse-battery-staple)
• Use a password manager — it generates and stores unique passwords for every site
• Enable two-factor authentication (2FA) wherever possible
• Never reuse passwords across different accounts

What Makes a Password Strong

Password strength is really about entropy — the number of guesses an attacker would need. Entropy grows with both length and variety: every extra character multiplies the possibilities, and mixing uppercase, lowercase, numbers, and symbols enlarges the pool each character is drawn from. Length matters most, which is why a long passphrase often beats a short, complex string.

Why Crack Time Is an Estimate

The crack-time figure assumes an attacker guessing offline at high speed. Real attacks are faster against predictable passwords — dictionary words, names, dates, and keyboard patterns like "qwerty" — because crackers try those first. A password with high raw entropy but built from a common phrase is weaker than the math suggests.

Practical Advice

Use a unique password for every account, favour length over cleverness, and let a password manager generate and store them. Create strong ones with the password generator. Note: this checker runs entirely in your browser — nothing you type is sent anywhere.