Passphrase Generator

A Diceware passphrase generator for passwords you can remember

A passphrase is a password made of several random words, such as stout-cider-gown-tutor-jolly-plank. This passphrase generator picks words uniformly at random from the EFF short word list — 1,296 short, common, easy-to-spell English words published by the Electronic Frontier Foundation for the Diceware method — using your browser’s cryptographic random number generator.

Random words are far easier to remember and type on a phone than q7#Vt!2m-style strings, and because each word carries about 10.3 bits of entropy, six of them give roughly 62 bits — and eight give about 83. That makes passphrases ideal for the few secrets you must actually memorise: your password manager’s master password, your computer login, or full-disk encryption.

Everything runs locally in your browser. The passphrases are never uploaded or stored; only your chosen settings are remembered on this device.

How to use the Passphrase Generator

1. Choose the number of words with the slider (3–12). Six words is a sensible minimum for important accounts; seven or eight for a password-manager master password.
2. Pick a separator — hyphen, space, period, underscore, comma, none, a random digit, or your own custom separator.
3. Choose capitalisation, and tick “Add a number” or “Add a symbol” if a website insists on them.
4. Set how many passphrases to show, then pick the one you find easiest to remember — choosing from a small list costs at most a few bits.
5. Press “Copy” next to the passphrase, or “Generate new” for a fresh set. Tick “Show dice rolls” to see the dice numbers for each word.

Passphrase Generator features

How passphrase entropy works

Each word is one of 1,296 equally likely choices, which is log₂(1,296) ≈ 10.34 bits. The strength of a passphrase therefore depends on the number of words, not on how long or unusual the words are. An attacker who knows you used this exact list and this generator still has to search 1,296ⁿ possibilities.

Worked example: 6 words = 6 × 10.34 = 62.0 bits, about 4.7 × 10¹⁸ combinations. Using a random digit as the separator adds 5 × log₂(10) ≈ 16.6 bits, while random capitalisation adds 1 bit per word. Adding a single digit to a random word adds log₂(10) + log₂(6) ≈ 5.9 bits.

Rolling your own passphrase with dice

Diceware was designed so that no computer is needed. Roll four ordinary six-sided dice (or one die four times), read the numbers in order — for example 3, 1, 5, 2 → 3152 — and look up the word with that number in the word list. Repeat for each word. Download the list with the “Word list (.txt)” button: each line shows the four-dice number and its word, from 1111 acid to 6666 zoom.

Physical dice are useful when you want to be certain that no software saw your passphrase. The tool’s “Show dice rolls” option shows which rolls would have produced each generated word, which also makes the method easy to learn.

Tips for using passphrases well

• Do not swap or reorder the words to make a sentence you like — keep what the generator gives you, or pick one from the list it shows.
• Never build a passphrase from song lyrics, quotes or a phrase that means something to you; attackers try those first.
• Keep a separator if you can. EFF short list #1 is not designed to be read without separators, so words could run together ambiguously.
• Use a random password generator for the dozens of accounts stored in your password manager, and a passphrase for the one password you must memorise.
• Curious how a phrase you already use measures up? Try the Password Strength Checker.