BIP39 Word List

The BIP39 word list is a standardized set of 2,048 unique words. It is defined in Bitcoin Improvement Proposal 39. Wallets use this list to encode a random number (entropy) into a human-readable mnemonic phrase. This phrase is commonly known as a seed phrase.

Each word in the list is carefully selected to be distinct and easy to recognize. This helps prevent mistakes when writing down or entering recovery phrases.

This reference list serves several practical purposes. You can use it to:

• Verify the correct spelling of each word in your seed phrase to prevent costly errors.
• Cross-check your recovery words against this standard to confirm validity.
• Reference numbered word indices for technical tasks, such as cryptographic calculations and wallet implementation.

Below is the full BIP39 wordlist. Click any letter to filter the list and find specific words quickly.

And below is a PDF version:

What Is BIP39?

BIP39, or Bitcoin Improvement Proposal 39, is a technical standard for wallets. It defines how to create mnemonic phrases, groups of easy-to-remember words used to back up and recover wallets.

These phrases are much easier to use than private keys. Private keys are usually 64-character hexadecimal strings, complex and error-prone to record or enter manually.

Example of mnemonic phrase (for educational purposes only):

float post gym list bullet garlic muscle wisdom reunion road rude drive

Example of private key (for educational purposes only):

20a50cad50de6d664a996e811db5a0889dcf6c15d38a133012f05f016ee6d6d9

The BIP39 standard consists of two main steps:

• Generating the mnemonic: A random number (entropy) is generated and encoded using a standardized list of 2,048 words. This results in a mnemonic phrase, usually 12 to 24 words long.
• Generating the seed: The mnemonic is combined with an optional passphrase to create a binary seed. This seed serves as the input for deterministic wallet generation, such as defined in BIP32.

This process ensures wallet recovery is both user-friendly and secure. It also maintains compatibility across different wallet platforms.

Read more: Differences Between Seed Phrases and Private Keys.

How Does the BIP39 Word List Work?

Each word in the list represents 11 bits of data. Since 2,048 = 2¹¹, each word can be uniquely identified by an 11-bit number.

When generating a mnemonic phrase, the wallet:

1. Generates a random entropy value (128 to 256 bits long)
2. Splits the entropy into chunks of 11 bits
3. Uses each 11-bit chunk to select a word from the BIP39 list
4. Presents the selected words in order as the mnemonic phrase

The length of the phrase depends on the entropy size:

• 128 bits → 12 words
• 256 bits → 24 words

The BIP39 word list was built with three core design goals in mind:

• Ensure interoperability: The word list is always used in the same fixed order. This consistency ensures that any compatible wallet can accurately reconstruct the original entropy and, from it, the wallet’s private keys.
• Avoid ambiguity: Words were chosen to be distinct in spelling and pronunciation. This helps prevent mistakes when users write down or read back their recovery phrases.
• Support global usability: The list uses simple English words that are easy to type and remember. It was designed to minimize confusion across different languages and keyboards.

While BIP39 includes word lists in multiple languages, using non-English lists is strongly discouraged for long-term security and wallet compatibility.

Where Is the BIP39 Word List Used?

The BIP39 standard is widely adopted across the Bitcoin and broader cryptocurrency ecosystem. It is used in the following types of wallets and tools:

• Hardware wallets: Devices like Ledger, Trezor, BitBox, and Coldcard use BIP39 to generate recovery phrases.
• Software wallets: Popular desktop and mobile wallets such as Bitcoin Core, Electrum, BlueWallet, and Wasabi Wallet use BIP39 for wallet setup and recovery.
• Seed phrase storage solutions: Products like Blockplate, Cryptosteel, and Seed Keys offer durable, metal-based backups for BIP39 seed phrases.
• Wallet libraries and development frameworks: Most developers use BIP39 when building wallet software or integrating wallet functionality. Libraries such as bip32utils, bitcoinlib, and libbitcoin implement BIP39 to ensure compatibility.

Any wallet that supports the BIP39 standard can correctly interpret and restore a mnemonic phrase, regardless of the original wallet used. However, users may need to adjust the derivation path or use compatible recovery options to ensure full access.

What Is a BIP39 Passphrase?

A BIP39 passphrase is an optional security feature used when generating a wallet seed.

When enabled, the seed is derived using both:

• The mnemonic phrase
• A user-defined passphrase (often called the “25th word” for simplicity)

This creates a different seed, and therefore a different wallet, than if the passphrase had not been used.

This means that even if someone has your mnemonic phrase, they still cannot access your wallet without also knowing the passphrase.

Use cases include:

• Plausible deniability: hiding a wallet behind multiple passphrases
• Extra protection: adding a second layer of security beyond the mnemonic

However, the passphrase is not recoverable. If it’s lost or mistyped, access to the wallet is permanently lost.

Unlike the mnemonic phrase, the passphrase is not standardized and may not be supported by all wallets. It should be stored separately, if used at all.

Because of the risks involved, a passphrase should only be used by advanced users who fully understand its implications.

Best Practices for Securing a BIP39 Seed Phrase

A BIP39 seed phrase is the single most important piece of data in managing Bitcoin self-custody. If lost or compromised, your coins can be permanently lost or stolen.

To protect against these risks, follow these key best practices:

• Store the phrase offline: Digital copies can be exposed through malware, theft, or accidental sharing.
• Use durable, tamper-evident storage: Metal-based seed phrase backups offer long-term protection against fire, water, and physical degradation, unlike paper.
• Keep it private: Never share your seed phrase with anyone, and avoid storing it in ways that make it easily accessible to others.
• Avoid single points of failure: Do not rely on a single storage method, backup, or location. Always plan for unexpected events like fire, theft, or natural disasters.
• Avoid unnecessary complexity: Adding a passphrase or splitting the phrase into parts increases risk of error and loss. Only use advanced techniques if necessary and fully understood.

Conclusion

BIP39 is a foundational standard in Bitcoin self-custody. It defines how cryptographic entropy is converted into a mnemonic phrase, a human-readable backup that allows users to recover their wallet and funds.

The BIP39 word list ensures consistency and interoperability across wallets. Each word represents 11 bits of data, and the full list of 2,048 words is used in a fixed order to generate seed phrases of varying lengths.

This standard is widely supported by hardware and software wallets, making recovery and migration possible across platforms, as long as the correct derivation paths are used.

While the BIP39 passphrase offers an optional second layer of security, it also introduces risks. If lost or mistyped, access to funds is permanently lost.

Because a seed phrase is the key to full control over Bitcoin, its long-term protection is critical. Paper fades, digital copies are vulnerable, and poor storage can lead to permanent loss.

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