BIP39 Mnemonic Phrase Generator
Description
Generate secure BIP39 mnemonic phrases (12–24 words) for cryptocurrency wallets with selectable entropy strength.
About BIP39 Mnemonic Phrase Generator
This tool generates BIP39 mnemonic phrases, the standard human-readable seed format used by most cryptocurrency wallets. A mnemonic of 12 to 24 words encodes a block of entropy (128 to 256 bits) plus a checksum, drawn from the fixed BIP39 word list. Anyone who holds the phrase can control the funds derived from it, so it must be kept secret and ideally stored offline. The phrase is generated locally in your browser and is never transmitted to a server.
How to use
- Select the entropy strength, which determines the word count (for example 128 bits for 12 words or 256 bits for 24 words).
- Click Generate to create a new mnemonic from the BIP39 word list.
- Write down the words in order and store them securely, preferably offline.
- Never paste your seed phrase into untrusted websites or share it with anyone.
Frequently asked questions
How many words should a BIP39 phrase have?
BIP39 supports 12 to 24 words. The count reflects the underlying entropy: 128 bits yields 12 words and 256 bits yields 24 words, with the last word incorporating a checksum.
What is the checksum for?
BIP39 appends a checksum derived from the entropy. It lets wallets detect typos or invalid phrases, since a random sequence of words is unlikely to have a valid checksum.
Why must I keep the phrase secret?
The mnemonic is the seed for your wallet. Anyone who knows it can regenerate your private keys and spend your funds, so it should be treated like the keys themselves: kept private and offline.
Is the phrase generated safely in my browser?
Yes. The mnemonic is created client-side from secure randomness and is not uploaded anywhere. For real wallet funds, generate seeds on a trusted, secure device.