BIP39 Seed Phrase Generator
Generate and validate BIP39 mnemonic seed phrases (12–24 words) and derive the seed — in your browser.
🔒 100% in your browser — nothing is uploaded
How it works
Generate a fresh BIP39 recovery phrase (12, 15, 18, 21 or 24 words) with a crypto-secure random generator, or paste an existing phrase to validate it and derive its entropy and seed. An optional passphrase acts as the BIP39 “25th word”. Everything runs in your browser — the phrase and seed never leave your device.
Never enter a seed phrase that holds real funds on any website. Use this for new or test phrases only.
Frequently asked questions
What is a BIP39 seed phrase?
A list of 12–24 common words that encodes the entropy behind a crypto wallet. Anyone with the phrase controls the wallet, so keep it secret and offline.
Is the phrase generated safely?
Yes — it uses your browser’s cryptographically-secure random generator via the audited @scure/bip39 library, and nothing is sent to any server.
What is the optional passphrase?
An extra secret (the BIP39 “25th word”) mixed into the seed. The same phrase with a different passphrase produces a completely different wallet.