Passphrase Generator (Diceware)
Pick random words from the EFF large wordlist (7,776 words) to build a passphrase that is easy to remember but hard to guess. Words are drawn with your browser's cryptographically secure random number generator (Web Crypto API) using rejection sampling to avoid bias, and nothing you generate is sent to a server. Need a random string with symbols instead? Try the Password Generator, and check a result with the Password Strength Checker.
🔒 Runs in your browser · Your data is never sent to a server
Word list: EFF Large Wordlist for Passphrases (© Electronic Frontier Foundation, licensed under CC BY 3.0 US).
How to use
- Choose the "Number of words" and the "Separator" (6 or more words is recommended)
- Optionally turn on "Capitalize each word" or "Add a digit to the end of one random word"
- Click "Generate" to see the result and its entropy
- Click "Copy" and store it in a password manager
Notes
- Passphrases are generated in your browser with the Web Crypto API and are never sent to a server. They cannot be reproduced after you leave the page, so save what you need in a password manager.
- Entropy is the theoretical value: number of words x log2(7,776), about 12.9 bits per word. It assumes the attacker knows the wordlist and the method. Capitalization and separators follow fixed rules, so they add nothing.
- When a digit is added, entropy increases for which word gets it (one of the words) and for the digit itself (10 options).
- Four words in the list contain a hyphen, such as drop-down and t-shirt.
- The word list (about 60 KB) is loaded the first time you generate.
Glossary
Diceware
A method of building a passphrase by rolling dice to pick words from a list. This tool uses secure random numbers instead of dice to choose from 7,776 words, the number of outcomes of five dice.
Entropy
A measure, in bits, of how hard a passphrase is to guess. Each word adds about 12.9 bits, so six words give about 77 bits.
Rejection sampling
A way to map random numbers onto a range without bias: values that fall into the uneven remainder are discarded and redrawn. Using only a modulo would make some words slightly more likely.
FAQ
How many words should a passphrase have?
Each word adds about 12.9 bits of entropy. Six words (about 77 bits) is a good default; use seven or eight for a master password or an encryption key.
Why is the Diceware method secure?
Words are picked by random numbers instead of by a person, so strength can be calculated from the word count. Even if an attacker knows the list and the method, the number of combinations from 7,776 words grows exponentially with each word.
Are generated passphrases stored or sent anywhere?
No. They are generated in your browser with secure random numbers and are never sent to a server. The word list is just a static file from this site.
Can I swap a word I do not like?
Rerolling individual words you dislike reduces the strength that random selection gives you. It is better to add a word or generate a fresh passphrase and use it as is.
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