Passphrase Generator
Generate a random, memorable, word-based passphrase locally in your browser using the standard BIP-39 word list — nothing is ever sent anywhere.
🔒 Processed locally in your browser
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How to use
- Choose how many words to include using the slider (4-10 words).
- Pick a separator: hyphen, space, underscore, or none.
- Optionally turn on Capitalize each word or Include a random number for extra complexity.
- Click Generate to create a new random passphrase, then Copy to copy it to your clipboard.
Features
- Cryptographically secure randomness (crypto.getRandomValues)
- Uses the standard 2048-word BIP-39 English word list (11 bits of entropy per word)
- Adjustable word count, separator, capitalization, and an optional random number
- Shows an estimated entropy in bits alongside the result
- 100% client-side — your passphrase is never sent anywhere
Frequently asked questions
Is this passphrase generator secure?
Yes. It uses your browser's cryptographically secure random number generator (crypto.getRandomValues), not Math.random(), and everything runs locally — nothing is ever transmitted.
Why use a word-based passphrase instead of a random-character password?
A passphrase built from random dictionary words is much easier to remember and type than a random string of characters, yet can be just as secure or more so: each word from the 2048-word list contributes about 11 bits of entropy, so a 6-word passphrase already has roughly 66 bits of entropy — comparable to or better than many shorter random-character passwords, while being far easier for a human to recall.
How is the estimated entropy calculated?
Each word is chosen from a 2048-word list, and log2(2048) = 11, so entropy is roughly word count x 11 bits. If you enable the random number option, about 3.3 more bits (log2(10)) are added for the extra digit. This is a reasonable approximation, not an exact cryptographic measurement.
Are the passphrase words always in English?
Yes. The words come from the standard BIP-39 English word list, which is a fixed, well-vetted set used for this kind of secure phrase generation. The generated words stay in English regardless of which language you're browsing this site in.
Are generated passphrases stored anywhere?
No. Passphrases exist only in your browser's memory while the page is open and are never saved or sent to a server.