BIP-39 Mnemonic Seed Phrase Generator & Validator
Generate and validate wallet recovery phrases, derive the seed.
About this tool
BIP-39 is the standard that turns a wallet's random entropy into a memorable list of words — the recovery phrase every crypto wallet asks you to write down. This tool generates valid mnemonics of 12 to 24 words from your browser's secure random generator, and validates phrases you paste, checking the built-in checksum that catches typos.
It also derives the 512-bit seed (with an optional BIP-39 passphrase, the '25th word') that wallets expand into keys. Built on the audited @scure/bip39 library, everything runs locally — but treat any phrase with real funds as radioactive and generate it offline.
Like everything on encrypt.tools, this runs entirely in your browser — nothing you enter is transmitted or stored.
Frequently asked questions about BIP-39 Mnemonic
Is it safe to generate a seed phrase in a browser?+
The phrase is generated locally from your device's secure random generator and never transmitted. For a wallet holding real value, however, best practice is to generate offline on an air-gapped or hardware device — malware on an online computer could in principle capture it. Use this tool for learning, testing, and validation.
What does the BIP-39 passphrase (25th word) do?+
It's an optional extra secret mixed into the seed derivation. The same 24 words with different passphrases produce completely different wallets, adding a layer of protection — but if you forget it, the funds are unrecoverable.
What does 'checksum valid' mean?+
BIP-39 phrases include a checksum built from the entropy, so not every combination of words is valid. A valid checksum means the phrase could have been generated correctly; an invalid one means a word is wrong or misspelled.
Related tools
Password Generator
High-entropy passwords with a live strength meter
DICEWARE · WORDSPassphrase Generator
Memorable word-based passphrases, diceware style
UUID · V4/V7UUID Generator
Random v4 and time-ordered v7 UUIDs, in bulk
TOTP · RFC 6238TOTP Generator
Live 2FA codes from a Base32 secret