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BIP39 Mnemonic Generator

Crypto wallet seed phrase · 12 / 15 / 18 / 21 / 24 words

⚠ Security warning: Generated phrases are computed locally with crypto.getRandomValues + SHA-256 — nothing leaves your browser. Use this only for testing or learning, NEVER for storing real funds. For production wallets, generate phrases offline on a hardware wallet (Ledger, Trezor) or air-gapped device.
Entropy (hex)

What is BIP39?

  • BIP39 is the Bitcoin Improvement Proposal that defines mnemonic seed phrases
  • An entropy → 11-bit indices into a 2048-word dictionary, plus a checksum (entropy/32 bits)
  • 12 words = 128-bit entropy (sufficient security for most wallets)
  • 24 words = 256-bit entropy (highest security, used by hardware wallets)
  • Same phrase + same derivation path = same wallet across compatible apps

How to store safely

  • Write the phrase on paper or stamped metal — never store digitally as plain text
  • Keep at least 2 copies in physically separated locations
  • Never type the phrase into any website or app for "verification" / "claim airdrop"
  • Anyone with your phrase has full control of your wallet — treat it like cash
  • Consider passphrase (BIP39 25th word) for extra security on long-term storage