BIP39 Mnemonic Generator & Validator
Generate or check a BIP39 seed phrase + checksum.
Runs entirely in your browser — nothing you enter is uploaded, logged, or tracked.
BIP39 turns random entropy into a memorable word list (your wallet “seed phrase”), with a checksum so typos are caught. This tool generates a valid mnemonic from your browser’s secure RNG, or validates a phrase you paste — checking every word against the 2048-word list and verifying the SHA-256 checksum. Everything runs locally.
Frequently asked questions
Should I use this for a real wallet?
No — never type a seed phrase that controls real funds into any website, including this one. Use it to learn how BIP39 works, to test, or to generate throwaway phrases. Real wallets should generate seeds on a hardware/offline device.
Is it uploaded?
No. Entropy comes from crypto.getRandomValues and all word/checksum math runs in your browser. Nothing is sent or stored.
What does the validator check?
That the word count is 12/15/18/21/24, that every word is in the official BIP39 English list, and that the final checksum bits match SHA-256 of the entropy — the same checks a wallet does.
What strengths are supported?
128-bit (12 words) through 256-bit (24 words) entropy, in the standard 32-bit steps. More words = more entropy.