Password Security Guide
Most passwords are weak. Learn what makes a password truly secure, how entropy is calculated, and how to protect your accounts without memorizing random strings.
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Use our free Password Generator or check your existing password with the Password Entropy Checker.
Why Most Passwords Fail
The most common passwords used worldwide are still things like "123456", "password", and "qwerty". Even "clever" substitutions like "P@ssw0rd" are trivially broken by modern cracking tools that use rule-based dictionaries.
Instant
Time to crack 'password'
< 1 second
Time to crack 'P@ssw0rd'
Centuries
Time to crack 16-char random
14 sites
Passwords reused on avg
What is Password Entropy?
Entropy measures how unpredictable a password is, expressed in bits. The higher the entropy, the longer it takes to crack by brute force. It is calculated as:
Entropy = length × log₂(pool_size) Where pool_size is: 26 — lowercase only 52 — lower + uppercase 62 — lower + upper + digits 94 — all printable ASCII
A 16-character password using all character types has ~105 bits of entropy — effectively uncrackable with current technology.
Entropy Strength Levels
Very Weak
< 28 bitsabc123Weak
28–35 bitsTr0ub4dorFair
36–59 bitsH7#mK9@nP2Strong
60–127 bitsX#9kL$mZ2qR7nW!vVery Strong
128+ bits32+ char randomPassword Best Practices
Use at least 16 characters
Length is the single biggest factor in password strength.
Use all character types
Mix uppercase, lowercase, digits, and symbols to maximize pool size.
Never reuse passwords
If one site leaks, attackers try the same password everywhere.
Use a password manager
Tools like Bitwarden or 1Password generate and store unique passwords.
Enable 2FA everywhere
Even a weak password becomes much harder to exploit with 2FA.
Avoid dictionary words
Even with substitutions, dictionary-based passwords are cracked quickly.
Passphrase vs Random Password
A passphrase like "correct-horse-battery-staple" (4 random words) has ~44 bits of entropy and is far easier to remember than a random string of the same entropy. For passwords you need to type regularly, passphrases are an excellent choice.
Passphrase
correct-horse-battery-staple~44 bits · memorable
Random
X#9kL$mZ2qR7~79 bits · stronger