Overview
Introduction
Traditional 'add a capital letter, a digit, and a symbol' password advice produces strings that are hard for humans to remember but not necessarily hard for computers to guess.
Diceware takes the opposite approach: pick several words uniformly at random from a large published list, which gives predictable, quantifiable entropy while staying memorable.
What Is Diceware Passphrase Generator?
A passphrase generator that selects words from the EFF's short word list, a curated 1,296-word list where every word has a unique 4-character prefix for easy autocomplete and error-checking.
You control the word count, the separator between words, whether words are capitalized, and whether a random 2-digit number is appended.
How Diceware Passphrase Generator Works
The tool fills a typed array with one cryptographically random 32-bit value per word via crypto.getRandomValues(), then maps each value onto the 1,296-word list by modulo — the same uniform-selection principle as rolling physical dice, just implemented in software.
It calculates and displays the exact entropy in bits for your current settings: word count times log2(1296), plus roughly 6.6 bits more if you enable the trailing number.
When To Use Diceware Passphrase Generator
Use it for a master password you'll need to type and remember often, like a password manager's unlock phrase or a full-disk encryption passphrase.
It's also a good source of memorable, unique-sounding words for things like temporary onboarding codes or Wi-Fi passwords you'll need to read aloud to someone.
Often used alongside Random String Generator, API Key Generator and Username Generator.
Features
Advantages
- Uses a cryptographically secure random source for word selection, not Math.random().
- Displays exact entropy in bits so you can judge strength quantitatively rather than guessing.
- Every word in the source list has a unique 4-character prefix, so typos are easy to catch and autocomplete works cleanly.
Limitations
- A passphrase is only as strong as its true randomness — anything that isn't drawn from this tool's random selection (like picking your own 'memorable' words) doesn't carry the same guarantees.
- The short word list trades a smaller word pool (1,296 vs. the original Diceware list's 7,776) for shorter, easier-to-type words, so each word contributes somewhat less entropy — use more words to compensate.
Examples
Best Practices & Notes
Best Practices
- Use at least 6 words for anything protecting high-value accounts or encryption keys.
- Keep the separator and capitalization simple and consistent so you can reliably retype the passphrase from memory.
- Check the displayed entropy figure against your threat model rather than assuming 'it's made of words' automatically means it's strong enough.
Developer Notes
Entropy is computed as wordCount × log2(wordlistLength), plus log2(100) ≈ 6.64 bits when the optional trailing number is enabled, and displayed alongside the generated passphrase so the security tradeoff of each setting is visible immediately.
Diceware Passphrase Generator Use Cases
- Generating a master password for a password manager
- Creating a full-disk encryption or backup encryption passphrase
- Producing a memorable Wi-Fi or shared-device password
Common Mistakes
- Reusing the same generated passphrase across multiple unrelated accounts — generate a fresh one per use case.
- Choosing too few words for a high-stakes secret; 3-4 words is far too little entropy for something like a full-disk encryption key.
Tips
- Enable the trailing number when a target system requires at least one digit in the password.
- A hyphen separator is usually the easiest to type reliably across keyboard layouts and input methods.