What this does
Generate passphrases made of random words, in the style of Diceware and the "correct horse battery staple" comic. Words come from the EFF large wordlist: 7,776 words chosen to be easy to spell and hard to confuse. Pick 3 to 24 words, a separator, a capitalization style, and optionally add a digit.
Why words work
Each word adds log2(7776), about 12.9 bits of entropy, regardless of how common it looks. Six words give about 77.5 bits and seven give about 90.5. The shown figure assumes an attacker knows your exact method and wordlist, which is the safe way to count. Separators and capitalization make the result easier to type or to satisfy a site's rules, but they do not add counted entropy. Adding a number adds a little, since the digit lands on a random word.
How it is generated
Each word is selected with crypto.getRandomValues and rejection sampling, so every word has exactly a 1 in 7,776 chance. The list is loaded only when you open this tool. Words are drawn independently, so a word can repeat, which is correct and keeps the entropy math exact.
Tips
- Use at least 6 words for a master password and 5 for most accounts.
- Never swap in a word you like better. Only the random choice carries the entropy.
- Words from this list include a few hyphenated entries such as
t-shirt; use a space separator if that matters to you.
Privacy
Passphrases are created in your browser and never uploaded, logged, or stored. The EFF wordlist is published under CC BY 3.0 US.