Generate strong, random passwords with a custom length and character set. Uses your browser's cryptographically secure random number generator.
A strong password resists both guessing and brute-force attacks, which come down to two factors working together: length and character variety, often summarized as entropy. A password is strong when it's long enough and random enough that testing every possible combination would take an attacker an impractically long time, even with modern hardware. Beyond length and randomness, a genuinely strong password should also be unique — never reused across multiple accounts, since a single data breach at one company can expose your password everywhere else you used it — and unpredictable, meaning it shouldn't be based on dictionary words, personal information (birthdays, pet names, addresses), or common patterns like 'Password123!' that appear at the top of every password-cracking wordlist.
The single most effective thing you can do is use a password manager to generate and store a unique, random, maximum-length password for every account, so you never have to remember or reuse anything — which is exactly the workflow this tool is designed to support.
There's a common misconception that a short, complex-looking password (like 'P@ssw0rd!') is stronger than a longer, simpler one — in reality, length matters more than complexity for resisting brute-force attacks, because entropy grows with every additional character, while character-set tricks (swapping 'a' for '@', 'o' for '0') barely help at all since attackers' cracking tools already account for these common substitutions. A 20-character password using only lowercase letters has a larger keyspace, and takes longer to brute-force, than an 8-character password using every character type available.
That said, length and character variety work together, not against each other — the strongest approach is to maximize both: use the longest password a given system allows, and include every character type it accepts. This is exactly why this tool defaults to 16 characters with all four character types enabled, and lets you push the length up to 128 characters for accounts where you want maximum protection and don't need to type the password by hand.
Entropy is the standard way to measure password strength mathematically, expressed in bits. It's calculated as length × log₂(pool size), where 'pool size' is the total number of possible characters at each position (26 for lowercase-only, 62 for upper+lower+digits, 94 for upper+lower+digits+symbols). Each additional bit of entropy doubles the number of guesses an attacker would need to try before finding your password by brute force, so entropy grows very quickly as you add length or character variety — going from 40 bits to 60 bits doesn't mean 50% more security, it means roughly a million times more possible combinations to search.
As a rough guide: below 40 bits is considered weak (crackable in hours to days with modern hardware), 40–60 bits is fair, 60–80 bits is strong, and above 80 bits is very strong (effectively uncrackable by brute force with current and near-future technology). This tool calculates entropy live from your exact settings and displays the resulting strength rating so you can see the real security tradeoff of any configuration change instantly, rather than guessing.
A password manager is the single most impactful security tool most people aren't using. It generates and stores a unique, maximum-strength password for every single account, so a breach at one company can never cascade into your other accounts being compromised too — a huge risk with password reuse, since credential-stuffing attacks (trying leaked username/password pairs against other sites) are one of the most common ways accounts get hijacked. Instead of remembering dozens of passwords, you only need to remember one strong master password (or use biometrics/hardware key) to unlock the manager itself.
When setting up a new account, generate a password here (or directly in your password manager, which offers the same capability), save it immediately, and never reuse it elsewhere. Enable two-factor authentication (2FA) wherever it's offered as an additional layer beyond the password alone. And periodically review your password manager's built-in breach-monitoring feature to catch and rotate any password that's appeared in a known data breach, even if the account itself hasn't shown signs of compromise yet.
Password Generator handles one piece of your security toolkit. These related developer tools cover hashing, unique identifiers, and encoding — all processed locally, just like this one.