BIP39 Mnemonic Generator

What is the BIP39 Mnemonic Generator?

The BIP39 Mnemonic Generator creates cryptographically secure seed phrases (mnemonic codes) for cryptocurrency wallets and other blockchain applications. BIP39, or Bitcoin Improvement Proposal 39, is the industry standard that defines how wallet seed phrases are generated from entropy and encoded as a sequence of human-readable words.

This tool generates everything client-side in your browser using the bip39 library. Your entropy and seed phrases never leave your device, ensuring complete privacy and security. You can choose from 10 language word lists and customize the entropy input to generate 12, 15, 18, 21, or 24 word mnemonics.

For other cryptography tools, try our Bcrypt Generator for password hashing, SHA-2 Hash Generator, or Password Generator for creating strong passwords.

How to Use the BIP39 Mnemonic Generator

1. Select your preferred Language for the word list from the dropdown (English, Chinese, French, and 7 more).
2. Entropy (hex) is pre-filled with a cryptographically random value. You can edit it manually or click the refresh button to generate new random entropy.
3. The Mnemonic Phrase updates instantly as you change the entropy or language.
4. Use the copy button to copy the mnemonic to your clipboard, or download it as a .txt file.

Entropy length determines the number of words in your mnemonic: 32 hex characters (128 bits) produces a 12-word phrase, while 64 hex characters (256 bits) produces a 24-word phrase. The length must be a multiple of 4 between 16 and 64.

Understanding BIP39 and Mnemonic Seed Phrases

BIP39 was introduced to make cryptocurrency wallet backups easier and less error-prone. Instead of requiring users to write down a long hexadecimal private key, BIP39 encodes that key into a sequence of words from a standardized word list. This makes recovery significantly more reliable since words are easier to write, read, and transcribe accurately than hex digits.

The process works as follows: random entropy (a cryptographically secure random number) is generated, a checksum is computed and appended, and the combined bits are split into groups that map to words in the chosen word list. The BIP39 specification includes word lists in 10 languages, all carefully selected to minimize ambiguity between similar words.

For related cryptographic operations, explore our Encryption tool or the HMAC Generator for message authentication.

Word List Languages and Compatibility

Our tool supports all 10 BIP39 word lists: English, Chinese Simplified, Chinese Traditional, Czech, French, Italian, Japanese, Korean, Portuguese, and Spanish. All word lists are compatible with each other at the BIP39 specification level, meaning a mnemonic generated in one language can be imported into any BIP39-compatible wallet regardless of the word list used.

The English word list is the most widely used and is the default for most hardware and software wallets. However, if your primary language is not English, using a word list in your native language can make your seed phrase easier to remember and verify.