Check password strength and entropy indicators.
The Password Strength Checker evaluates how resistant a password is to brute-force and dictionary attacks. It estimates the number of possible combinations (entropy), the time to crack at typical attack speeds, and identifies specific weaknesses: common patterns like 'password123', keyboard walks like 'qwerty', dictionary words, and predictable substitutions like 3→E or 0→O. A strong password is long (12+ characters), uses all character types, and is not based on any dictionary word, name, or predictable pattern.
Length is the biggest factor. A random 16-character password of any characters is much stronger than a complex 8-character password. Use a combination of uppercase, lowercase, digits, and symbols. Avoid any word found in a dictionary, any part of your name or email, and any repeated pattern.
Common substitutions (a→@, o→0, e→3) are known to attackers. Cracking tools try these patterns automatically. A password that was a word before substitution is still a dictionary word in terms of crack resistance.
A passphrase is a sequence of random words: 'correct horse battery staple'. At 4 random words, this has more entropy than most 8-character passwords and is far easier to memorize. NIST SP 800-63B recommends passphrases over complex short passwords.