Password Security, Quick Facts
- •Password strength is measured in bits of entropy: length × log₂(character pool size). More bits means exponentially more guesses needed to crack it.
- •A 12-character password using only lowercase letters has about 56 bits of entropy. Add uppercase, numbers, and symbols at the same length and it reaches over 75 bits.
- •This generator uses the Web Crypto API (
crypto.getRandomValues), a cryptographically secure random source, notMath.random(), which is not safe for anything security-related. - •Length matters more than complexity rules. A long random password usually beats a short "complex" one that follows predictable substitution patterns.
The Real Problem This Solves
Reused, predictable passwords are the number one cause of account takeovers, not sophisticated hacking, just guessing or reusing a password leaked from a completely different breach.
Humans are bad at generating true randomness; we default to patterns, dictionary words, and predictable substitutions like "P@ssw0rd". A proper generator removes that human bias entirely.
How Password Strength Is Calculated
Entropy in bits equals length × log₂(pool size), where pool size is how many possible characters could appear at each position. This number represents how many attempts, on average, an attacker needs to try every possibility before finding your password by brute force.
Example: a 16-character password using lowercase, uppercase, numbers, and symbols (a pool of 89 characters) has about 104 bits of entropy, roughly 2¹⁴⁴ possible combinations, far beyond what any current hardware can brute-force in a meaningful timeframe.
| Length | Character Types | Approx. Entropy | Rating |
|---|---|---|---|
| 8 | Lowercase only | ~38 bits | Weak |
| 12 | Lower + Upper + Numbers | ~71 bits | Good |
| 16 | All types | ~104 bits | Strong |
| 24 | All types | ~156 bits | Strong |
Frequently Asked Questions
Is Math.random() safe for generating passwords?
No. Math.random() is a fast, predictable pseudo-random generator meant for things like animations or games, not security. This tool uses the Web Crypto API's getRandomValues(), a cryptographically secure random number generator (CSPRNG) designed specifically for this purpose.
Should I exclude ambiguous characters like l, 1, I, and O?
Only if you expect to type the password manually, for example from a printed sheet. If you're using a password manager (recommended), there's no need, every character is equally easy to copy and paste.
How long should my password be?
At least 12 characters for anything important, 16+ where possible. Length contributes more to security than character variety, a longer password is almost always stronger than a shorter, more "complex" one.
Is this password stored or sent anywhere?
No. It's generated entirely in your browser using the Web Crypto API and never leaves your device or gets logged anywhere.
Should I reuse the same strong password everywhere?
No. Use a unique password for every account, ideally managed by a password manager, so a single breach never exposes your other accounts.
Need a random ID instead of a secret?
A password is meant to be secret. For a random, non-secret unique identifier instead, like a database key or request ID, generate one with our UUID Generator.
Open UUID Generator →