Password Generator
Strong random passwords and passphrases, generated in your browser with real entropy.
Worth excluding for anything you may have to read aloud or retype.
Generated entirely in your browser using the operating system's secure random source. Nothing is transmitted, logged or stored, and reloading the page loses everything shown here.
How it works
Every password here comes from <code>crypto.getRandomValues</code>, the browser's cryptographically secure random source, drawn from the operating system's entropy pool. That distinction matters: the ordinary <code>Math.random</code> is a predictable generator seeded from a small state, and passwords built from it have been recovered in practice.
Characters are selected by rejection sampling rather than by taking a random number modulo the alphabet size. Modulo introduces a slight bias toward the early characters of the set whenever the alphabet does not divide evenly into the random range — small, but it is a real reduction in entropy and there is no reason to accept it.
The strength figure is honest arithmetic, not a coloured bar. Entropy is <code>log₂(alphabet^length)</code> for characters, or <code>log₂(wordlist^words)</code> for a passphrase, and the crack time assumes an attacker who has stolen the password database and is guessing offline at 100 billion per second — achievable with rented hardware against a weak hashing scheme. That is deliberately pessimistic. Against a well-built site using bcrypt or Argon2, a real attacker manages a few thousand guesses per second, and every figure here becomes astronomically better.
Passphrases are worth understanding properly. The list here holds exactly 256 words, so each one contributes exactly eight bits and the arithmetic stays checkable: seven words is 56 bits, ten words is 80. That is comparable to a random character password of nine and fourteen characters respectively — far easier to type on a phone or a games console, and far easier to remember.
The catch is that this only holds when the words are chosen randomly. A phrase you thought of yourself is not seven random words; it is one memorable idea, and an attacker guessing phrases rather than characters will find it. A short list is not a weakness — entropy is entropy — it simply means you need more words.
The honest advice is that you should not be typing most of these. Use a password manager, let it generate long random strings you never see, and keep exactly one strong passphrase — the one that unlocks the manager — in your head.
Common questions
How long should a password be?
For a random-character password with a full alphabet, 16 characters is comfortable and 20 is generous. Length buys far more than complexity does: adding one character multiplies the work by the size of the alphabet, while adding one more symbol type barely moves it.
Are passphrases really as strong?
Yes, if the words are chosen randomly, and the arithmetic is shown on the page so you can check it. The list here is 256 words, so each word is exactly eight bits: seven words is 56 bits. The failure mode is picking the words yourself — that is a memorable phrase, not a random one, and it falls to a completely different and much faster attack.
Should I change passwords regularly?
No. Forced rotation is advice that has been formally withdrawn — NIST dropped it — because it pushes people toward predictable variations like Summer2024 becoming Summer2025. Change a password when you have reason to think it is exposed, and otherwise leave a strong unique one alone.
Why exclude lookalike characters?
Because l, I and 1 are indistinguishable in many fonts, as are O and 0. It costs a little under three bits of entropy on a twenty-character password, which is nothing, and it saves you from a password that cannot be reliably read off a screen or dictated over the phone.