BIP39 Mnemonic Generator

Generate and validate BIP-0039 mnemonic seed phrases. Entropy comes from Web Crypto (crypto.getRandomValues), the checksum is SHA-256, and the seed is derived with PBKDF2-SHA512 (2048 iterations). Everything runs locally — your entropy and mnemonic never leave your browser.

Entropy strength

Passphrase (optional)

Number the words

—

Entropy (hex): —

Seed (hex): —

BIP-0039: entropy bits → append first ENT/32 bits of SHA-256(entropy) as checksum → split into 11-bit groups → map each to a word. The seed is PBKDF2-SHA512 with 2048 iterations over the mnemonic and "mnemonic"+passphrase as salt. The wordlist is the official English list (2048 words). Runs entirely in your browser.