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BIP39 Mnemonic Generator

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Testing / learning only. Do not use a mnemonic generated in a browser to hold real cryptocurrency funds — generate real wallet seed phrases offline, on an air-gapped device or hardware wallet.

Validate

Generate a 12–24 word BIP39 mnemonic and validate any phrase's checksum, in a page with no wallet-address derivation, no client-configuration clutter, and a warning that stays visible instead of buried in the fine print. Testing and learning only — not for real funds.

This tool is for informational purposes only and is not a substitute for professional financial or medical advice. Consult a qualified professional before making decisions. See our Disclaimer.

How it works

  1. A 12-word mnemonic appears immediately on load
  2. Change the word count (12–24) to regenerate at a different entropy strength
  3. Paste any mnemonic into the validate box to check its wordlist and checksum instantly

Frequently asked questions

Can I use a mnemonic from this tool for a real wallet?

No — a browser-generated mnemonic isn't appropriate for holding real funds. Generate real wallet seed phrases offline, on an air-gapped device or hardware wallet. This tool is for testing and learning.

What's the difference between a 12-word and 24-word phrase?

More words encode more entropy (128 bits vs 256 bits). 12 words is already effectively unbreakable by brute force, but 24 words gives a larger theoretical security margin.

Is my mnemonic sent to a server?

No — generation and validation both run entirely in your browser.

What happens if I paste an invalid mnemonic?

You'll see exactly why it's invalid — an unrecognized word, a checksum mismatch, or an unsupported word count.

Does this support other languages besides English?

Not yet — this tool currently supports the BIP39 English wordlist only.

#Bip39MnemonicGenerator#Bip39SeedPhraseGeneratorOnline#Bip39ChecksumValidator#12WordVs24WordSeedPhrase#Bip39WordListEnglish

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From the blog

BIP39 tools bolt on address derivation, client configs, and clone-site branding. We left all of it out.
dev

BIP39 tools bolt on address derivation, client configs, and clone-site branding. We left all of it out.

The best-known BIP39 tool has been cloned under near-identical names, and its full-featured forks bury a real security warning under derivation paths and client settings. We kept this one narrow on purpose.

2026-08-30

Update history

  • 2026-08-30 Added: a cover image (a vault holding a numbered recovery-phrase card, with an unplugged cable and a warning badge signaling offline/testing-only) — used as the card thumbnail, social share image, and blog title image.
  • 2026-08-30 Launched: live BIP39 mnemonic generator (no button) — 12–24 word generation and checksum validation, using the audited @scure/bip39 library, entirely client-side. No address derivation or client-config clutter by design, and a warning banner that stays visible above the result rather than buried in body text.