How do I generate a diceware passphrase?

Set Number of words with the slider (3 to 10), pick a Separator, then click Generate new. Click Copy to copy it. Click any single word to reroll only that word.

How many words should my passphrase have?

The tool labels the length by entropy: weak, ok, strong or very strong. Each word adds about 10.3 bits, so 6 words gives roughly 62 bits. Use more words for higher-value secrets.

Where do the words come from and how random are they?

Words are picked from a bundled list of 1,296 words using crypto.getRandomValues with rejection sampling to avoid bias. Generation runs in your browser with no network request.

What do Capitalize and Append a random number do?

Capitalize makes each word start with an uppercase letter and adds no entropy. Append a random number adds a number for sites that require digits.

How is the crack time calculated?

Entropy is word count times log2 of 1,296. The Time to crack figure assumes one of three attacker speeds: online at 10 guesses per second, offline GPU at 10 billion, or nation-state at 100 trillion.

Yes. Every tool is free to use, with no account and no credit card. The work runs on your device rather than on our servers, which is what keeps it free to run.

Does it work on mobile?

Yes. It runs in current mobile browsers on iOS and Android, with nothing to install.

🎲

Free Diceware Passphrase Generator

Generate memorable, high-entropy passphrases by combining random words. Configurable word count, separator, and capitalization — uses cryptographically secure randomness.

Runs in your browserNo sign-up, no pop-upsNo login requiredFree forever

Works offline once loaded

...

Click any word to reroll just that word

62 bits

Entropy

15 years

Time to crack

Number of words (6) — ok

Separator

Capitalize first letter of each wordAppend a random number (for sites that require digits)

Why diceware? Memorable phrases of random words have huge entropy and are easier to remember than gibberish. A 5-word phrase has more entropy than a 10-character random password with mixed case + symbols. All randomness comes from crypto.getRandomValues() in your browser. No words, passphrases, or any data are sent anywhere.

Common uses

Generate Master Password for Password ManagersA diceware passphrase is ideal for your password manager master key — high entropy, memorable.
Generate Encryption PassphrasesFor full-disk encryption, GPG keys, or any cryptographic system that needs a memorable secret.
Generate Wi-Fi Network PasswordsEasier to share verbally than random gibberish — perfect for guest networks or shared homes.
Generate Shared Team SecretsFor shared service accounts, deployment passwords, or anything multiple humans need to remember.
Generate Memorable Example Passwords for DemosWhen demoing tools that need a password, diceware phrases are more memorable for audiences than gibberish.

How It Works

Passphrase generation runs entirely in your browser using the Web Crypto API's crypto.getRandomValues — the same cryptographic randomness source used by password managers and TLS. The 1,296-word EFF short wordlist is bundled directly in the page, so no network request is made during generation.

1
Bias-free word selection
For each word slot, crypto.getRandomValues fills a Uint32 buffer with a hardware-backed random number. Rejection sampling discards values that would skew the distribution, then the result indexes into the 1,296-word EFF short wordlist — giving exactly 10.34 bits of entropy per word with no modulo bias.
2
Optional extras appended
If you enable the number toggle, a random integer from 0–99 is chosen with the same bias-free method and appended as a separate chip, adding approximately 6.6 bits. Capitalizing the first letter of each word is deterministic and adds no entropy, which the tool notes explicitly.
3
Live entropy and crack-time display
Entropy is computed as wordCount × log2(1296), and the tool converts that figure to an estimated crack time using three selectable attack models: 10 guesses/sec (online throttled), 10 billion/sec (offline GPU), and 100 trillion/sec (large-scale cluster). The math updates instantly as you change word count or options.
4
Per-word reroll and copy
Clicking any individual word replaces only that word with a freshly generated one — same entropy, useful for swapping out an awkward word without regenerating the entire passphrase. The final string is assembled with your chosen separator and written to the clipboard via the standard Clipboard API.