What Is a Strong Password?
A strong password is one that's genuinely difficult for both automated tools and other people to guess. In practice, that comes down to three things working together: sufficient length, real randomness across the full range of characters used, and no connection to information about you that someone could look up or guess. A password can look complicated — mixed case, numbers, symbols — and still be weak if it's built from a recognizable word or a predictable pattern, since password-cracking tools are specifically designed to test exactly those patterns first.
The generator above avoids this problem at the source: each character is chosen independently using your browser's cryptographically secure random number source, so the result has no underlying pattern for a cracking tool to exploit, regardless of how the password happens to look.
Why Password Length Matters
Length has an outsized effect on how hard a password is to crack because it increases the total number of possible passwords exponentially, not just proportionally. Each additional character multiplies the number of combinations an attacker would need to try, which is why a longer password is generally a more effective way to increase security than adding complexity to a short one. Most current guidance suggests at least 12 characters as a practical minimum, with 16 or more recommended for accounts that matter, such as email, banking, and any account used to recover access to other accounts.
| Length | Approx. entropy (full character set) | Practical assessment |
|---|---|---|
| 8 characters | ~52 bits | Weak — acceptable only for disposable accounts |
| 12 characters | ~79 bits | Reasonable minimum for everyday accounts |
| 16 characters | ~105 bits | Strong, recommended default for most accounts |
| 20+ characters | ~131+ bits | Excellent for email, banking, or a password manager's master password |
Why Password Uniqueness Matters
A strong password loses much of its value if it's reused across multiple accounts. When one website suffers a data breach, attackers routinely test the exposed email-and-password combinations against other popular sites — a technique known as credential stuffing. If you've reused a password, a breach that has nothing to do with you directly can still expose accounts you actually care about. Using a different, independently generated password for every account removes this risk entirely, regardless of how strong any individual password is.
Why Random Passwords Are Better Than Predictable Ones
People are consistently worse at generating genuine randomness than they think, even when trying deliberately. Manually chosen "random" passwords tend to favor certain letters, avoid repetition in ways true randomness wouldn't, and often incorporate small personal references without the person realizing it. Automated cracking tools are built around exactly these tendencies. A properly implemented generator has no such bias: every character is selected independently, with no psychological pattern underneath for an attacker's software to recognize.
Password Managers and Strong Passwords
A password with enough length and randomness to be genuinely strong is usually too long to memorize comfortably, which is exactly the problem a password manager solves. Generate a password here, save it in a reputable password manager, and let it autofill the credential going forward. This makes it practical to use a unique, high-entropy password for every account you own, rather than settling for something memorable but weaker.
Multi-Factor Authentication
Multi-factor authentication (MFA or 2FA) adds a second proof of identity beyond your password — a code from an authenticator app, a prompt to your phone, or a hardware security key. It matters because it protects you in situations password strength alone cannot, most notably phishing, where a password is handed over voluntarily to a fraudulent page. Enabling MFA wherever it's offered, particularly for email, banking, and any account that recovers access to others, meaningfully reduces your overall risk beyond what password strength alone can provide.
Common Password Mistakes
- Using names, birthdays, or phone numbers that a targeted attacker could discover or guess from publicly available information.
- Reusing the same password across multiple accounts, exposing every one of them to a single breach.
- Relying on predictable patterns, such as a word followed by a number and a symbol, which cracking tools specifically test for.
- Choosing a shorter password for convenience, trading meaningful security for a small amount of typing time.
- Storing passwords in an unencrypted note or document instead of a proper password manager.
How to Create a Secure Password
- Use the generator above with a length of at least 12 characters, or 16 or more for important accounts.
- Keep all four character types enabled unless a specific site restricts them.
- Generate a new, independent password for every account rather than reusing or slightly modifying one.
- Save the result in a password manager rather than trying to memorize it.
- Enable multi-factor authentication wherever the account offers it.
Understanding Entropy
Entropy, shown above as an estimate in bits, is a way of measuring how large the search space for a password actually is. It's calculated from the password's length and the number of distinct characters it could draw from at each position; more length and more character variety both increase it. A higher entropy value generally means a larger number of guesses would be required to find the password through brute-force searching, but entropy is one useful signal among several, not a standalone guarantee — a password's real-world security also depends on it being unique and kept private.