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Diceware Passphrase Generator

Generates passphrases from the full EFF long wordlist, 12.9 bits a word, and shows the five-dice roll behind every word.

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Security tool
Fill in the fields and press Generate passphrases.
In short Diceware works because 7,776 is 6⁵, so five ordinary dice choose one word from the list with no bias and no computer involved — roll them, read the five numbers as one code, look it up, repeat. Each word is worth log₂(7,776) = 12.925 bits, and the strength of the result is that figure multiplied by the number of words, on the assumption the attacker already has the wordlist and knows the method. That assumption is the whole point: the security is in the dice, not in secrecy about how it was made. The number that surprises people is how many words are needed. Four EFF words is 51.7 bits, which an offline GPU cluster at 10¹¹ guesses a second gets through in about five hours. Six words is 77.5 bits and the same cluster needs roughly 35,000 years — which is why six is the EFF's own recommendation. Capitalising the first letter of each word adds nothing at all, because a rule an attacker knows is not entropy; a randomly chosen digit adds log₂(10), about 3.3 bits.

How to use the Diceware Passphrase Generator

  1. Choose how many words — six unless you have a reason for more.
  2. Press Generate. Each passphrase shows the five-dice roll behind every word.
  3. Read the entropy figure and the crack time before accepting one.
  4. For anything high value, roll five real dice instead and use the codes to pick your own words from the same list.

About the Diceware Passphrase Generator

The Diceware Passphrase Generator generates passphrases from the full EFF long wordlist, 12.9 bits a word, and shows the five-dice roll behind every word. It runs as plain JavaScript inside the page, which means there is no upload step, no queue and no size limit imposed by a server — the only limit is your own device.

What people use it for

  • Choosing a password manager master password you have to type from memory.
  • Setting a disk encryption or device login passphrase.
  • Generating a phrase on screen, then re-rolling it on real dice for something high value.

Details

WordlistThe EFF long list — 7,776 words, used verbatim and self-hosted
Entropy per word12.9248 bits, against 11 for a 2,048-word list
Six words77.5 bits — about 35,000 years for an offline GPU cluster
Randomnesscrypto.getRandomValues with rejection sampling, so all 7,776 words are equally likely
DiceEvery word shows its five-dice code, so you can reproduce it by hand
NetworkNothing is generated on a server and nothing is sent — check your Network tab
The wordlist is the EFF long list by Joseph Bonneau, used verbatim and self-hosted, licensed CC BY 3.0 US. The original is at eff.org/dice. Its file is 7,776 lines with dice codes from 11111 to 66666; this page stores the words only, because the list is in dice order and the code for word n is simply n written in base six.

Where this tool stops

Generates on screen using your device's cryptographic random generator. That is not the same trust model as physical dice, and for a key whose loss would be catastrophic the dice are still worth the ten minutes.

Explained in our guides

All guides

Frequently asked questions

Why 7,776 words?
Because it is 6⁵. Five dice produce exactly 7,776 equally likely outcomes, so every word can be selected by one roll with nothing left over and no bias — no re-rolling, no discarding, no arithmetic. A list of any other size breaks that correspondence, which is the entire reason diceware lists are this length.
How many words do I actually need?
Six. Four is 51.7 bits and an offline GPU cluster gets through it in about five hours; five is 64.6 bits and takes a few years; six is 77.5 bits and takes tens of thousands. Seven or eight are worth it for a disk encryption key you will type rarely, but six is the EFF's recommendation and it is the right default.
Does capitalising the words make it stronger?
No, and the tool refuses to pretend otherwise — the entropy figure does not move when you turn it on. "Capitalise the first letter of every word" is a rule, and an attacker guessing diceware phrases applies the same rule for free. Only a genuinely random choice adds entropy, which is why the digit option adds 3.3 bits and the capitals add zero.
Is generating it in a browser as safe as rolling dice?
For nearly everything, yes: <code>crypto.getRandomValues</code> is the operating system's cryptographic generator, and this page never transmits what it produces. Physical dice remove one more assumption — that your device is not compromised and its generator is not backdoored — which is why they are still the right answer for a key protecting something that would be catastrophic to lose. The dice codes are printed next to every word so you can do exactly that.
How do I roll it by hand?
Roll five dice and read them left to right as a five-digit number — 4, 1, 6, 2, 3 becomes 41623. Look that code up in the EFF list. Repeat six times. If you only have one die, roll it five times in a row instead. There is no step where a computer is involved.
Why does the list contain words with hyphens?
Four of the 7,776 do — <code>drop-down</code>, <code>felt-tip</code>, <code>t-shirt</code> and <code>yo-yo</code>. They are in the official list and are kept, because removing them would change the count and break the correspondence with five dice. If a password field rejects hyphens, choose a different separator or generate again.
Can I use a passphrase everywhere?
You should not need to. Use one for the handful of passwords you genuinely have to memorise — device login, password manager master password, disk encryption — and let the manager generate long random strings for everything else. A memorable passphrase reused across sites is still a reused password.
Is there a limit on how often I can use the Diceware Passphrase Generator?
Free, unlimited, and no email address required. You can use it a hundred times a day and nothing changes.
Is what I paste into the Diceware Passphrase Generator stored?
No. The Diceware Passphrase Generator runs entirely in your browser using JavaScript. Nothing is transmitted, logged or stored, which you can verify yourself in the Network tab of your browser's developer tools.
What is the Diceware Passphrase Generator used for?
The jobs it is built for: choosing a password manager master password you have to type from memory. Setting a disk encryption or device login passphrase. Generating a phrase on screen, then re-rolling it on real dice for something high value. It is built for exactly those cases rather than being a general-purpose tool with this bolted on.
What are the limits of the Diceware Passphrase Generator?
Generates on screen using your device's cryptographic random generator. That is not the same trust model as physical dice, and for a key whose loss would be catastrophic the dice are still worth the ten minutes. Knowing where a tool stops being trustworthy matters more than the cases where it works.
What are the reference figures here?
Wordlist is The EFF long list — 7,776 words, used verbatim and self-hosted. Entropy per word is 12.9248 bits, against 11 for a 2,048-word list. Six words is 77.5 bits — about 35,000 years for an offline GPU cluster. These are printed on the page itself, so you do not have to take them on trust.
Can I use the Diceware Passphrase Generator on mobile?
Yes. The page is responsive and the tool works in Chrome, Safari, Firefox, Edge and Samsung Internet on both Android and iOS. There is no app to install and nothing to sign into.

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