Generate a BIP39 passphrase from an existing or random mnemonic, or get the mnemonic from the passphrase.
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About BIP39 passphrase generator
Generates a BIP39 mnemonic phrase of 12, 15, 18, 21 or 24 words, or converts between a mnemonic and its hex entropy in either direction. It validates the checksum, supports ten official wordlists (English, Spanish, French, Italian, Portuguese, Czech, Japanese, Korean and both Chinese lists) and derives the 512-bit seed with an optional passphrase. Everything runs in your browser, but a web page is still not a safe place for a phrase that will hold real funds.
Common uses
- Create test mnemonics for wallet development and unit tests
- Check whether a mnemonic is valid and find which word is wrong
- Convert raw entropy to a mnemonic or a mnemonic back to entropy
- See how an optional passphrase changes the derived seed
FAQ
- How many words should a BIP39 mnemonic have?
- BIP39 allows 12, 15, 18, 21 or 24 words, corresponding to 128 to 256 bits of entropy in 32-bit steps. 12 words (128 bits) and 24 words (256 bits) are the most common.
- What is the BIP39 passphrase or '25th word'?
- It is an optional extra string mixed into seed derivation. The same mnemonic with a different passphrase produces a completely different seed and therefore different wallets.
- How is the BIP39 seed derived?
- The seed is PBKDF2-HMAC-SHA512 of the mnemonic, using the string 'mnemonic' plus the passphrase as the salt and 2048 iterations, producing 512 bits.
- Why is my mnemonic invalid if all words are in the list?
- The last word contains a checksum derived from the entropy. If words are swapped or one is changed, the checksum no longer matches and the phrase is rejected.