BIP39 Mnemonic Generator
Generate BIP39 seed phrases used by many Bitcoin, Ethereum, and multi-chain wallets.
What it does
BIP39 mnemonics encode random entropy plus a checksum as words from a fixed 2048-word list. This generator uses official BIP39 wordlists and browser Web Crypto APIs.
BIP39 seed phrases are commonly used by Bitcoin wallets, Ethereum wallets, hardware wallets, and multi-chain wallet apps. The same mnemonic standard can be used for BTC, ETH, EVM networks such as Polygon, BNB Smart Chain, and Avalanche, and many wallets for coins such as Solana, Litecoin, Dogecoin, Cosmos, and Cardano.
People often call the same thing a seed phrase, recovery phrase, Secret Recovery Phrase, wallet backup phrase, recovery seed, seed words, mnemonic seed, or 12-word or 24-word phrase.
The word count controls the entropy size: 12 words use 128 bits, while 24 words use 256 bits. Longer phrases are common for high-value wallets and offline backup workflows.
Common uses
- Generate test wallet seed phrases for Bitcoin, Ethereum, EVM-chain, hardware-wallet, and multi-chain wallet development.
- Use 12 words for common compatibility tests and 24 words when you want the largest standard BIP39 entropy size.
- Test recovery phrase import flows for wallets that support BIP39, including Bitcoin, Ethereum, and major multi-coin wallet interfaces.
- Choose a language when testing wallet flows that support localized BIP39 wordlists.
Watch outs
- Treat any real wallet recovery phrase as a secret. Anyone with the words can control funds protected by that seed.
- For production funds, prefer the generator built into a trusted hardware wallet or an offline environment you control.
- BIP39 creates the mnemonic and seed. It does not choose a coin, derive an address, or select a derivation path for you.
- Bitcoin, Ethereum, Solana, Cardano, and other coin wallets may use different derivation paths or account rules. Import the phrase only into wallets that support the language and path you expect.
- English remains the safest compatibility default because some wallets do not support every BIP39 language.
- Do not paste an existing wallet phrase into online tools. This page generates new phrases and does not need your current seed.
Privacy
Mnemonic generation happens in your browser with Web Crypto randomness. Generated words are not sent to Crypto Lambda.
FAQ
Are these valid BIP39 phrases?
Yes. The generator creates the correct amount of random entropy, adds the BIP39 checksum, and maps the result to the selected official wordlist.
Is a 12-word BIP39 seed phrase secure enough?
A properly generated 12-word BIP39 phrase has 128 bits of entropy, which is considered very strong against guessing. The bigger practical risks are weak randomness, phishing, screenshots, cloud backups, malware, and typing the phrase into the wrong place. Use 24 words if you want the largest standard BIP39 entropy size.
How can I make a BIP39 wallet more secure?
Use a trusted hardware wallet or offline environment, write the recovery phrase on durable offline storage, never store it in screenshots or cloud notes, and consider adding a BIP39 passphrase. The optional passphrase is sometimes called a 25th word, but it can be any text and creates a different wallet from the same seed phrase.
What is a BIP39 passphrase or 25th word?
A BIP39 passphrase is an optional extra secret mixed with the seed phrase when deriving wallet keys. It can protect funds if someone finds the recovery phrase, but it is also dangerous to forget: the same 12 or 24 words without the exact passphrase open a different wallet.
What do people call BIP39 if they do not know the term?
Common names include seed phrase, recovery phrase, Secret Recovery Phrase, wallet backup phrase, recovery seed, seed words, mnemonic phrase, mnemonic seed, 12-word phrase, 24-word phrase, crypto recovery words, and sometimes private key phrase or wallet key phrase.
Does BIP39 work with Bitcoin and Ethereum?
Yes, many Bitcoin and Ethereum wallets use BIP39 recovery phrases. Bitcoin wallets then derive BTC addresses with paths such as BIP44, BIP49, BIP84, or BIP86, while Ethereum and many EVM wallets commonly derive ETH-style accounts from the same BIP39 seed standard.
Which major coins and wallets use BIP39?
BIP39 or BIP39-compatible recovery phrases are common in hardware wallets and multi-chain wallets for Bitcoin, Ethereum, EVM networks such as Polygon, BNB Smart Chain, and Avalanche, and many wallets for Solana, Litecoin, Dogecoin, Cosmos, and Cardano. Exact support depends on the wallet and derivation path.
Is this a Bitcoin or Ethereum address generator?
No. This page generates the BIP39 mnemonic phrase only. It does not derive private keys, public keys, wallet addresses, xpubs, or coin-specific accounts.
Can one BIP39 phrase back up multiple coins?
Often yes. A single BIP39 seed can be used by compatible wallets to derive separate accounts for Bitcoin, Ethereum, EVM chains, and other supported networks. The mnemonic is shared, but each coin still depends on its wallet software, derivation path, and account index.
Which languages are supported?
English, Chinese simplified, Chinese traditional, Czech, French, Italian, Japanese, Korean, Portuguese, and Spanish.
Which word count should I use?
Use 12 words for common wallet compatibility tests. Use 24 words when you want the largest standard BIP39 entropy size.
Can Crypto Lambda see the generated phrase?
No. The page is served by Crypto Lambda, but the random entropy, checksum, and words are generated locally in your browser.
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