Online Tool Store
Random Seed Phrase Generator
Generate a standards-compliant BIP39 mnemonic (12-24 words) using the official 2048-word wordlist and a cryptographically secure random generator, or verify an existing phrase's wordlist and checksum. Runs entirely in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Only affects Copy — Download always uses the standard space-separated format.
How the seed phrase generator works
- Choose how many words you want (12-24) and your preferred copy separator.
- Click "Generate new phrase" for a fresh, BIP39-checksum-valid mnemonic drawn from cryptographically secure randomness.
- Copy, download, or print a backup card - or switch to Verify to check an existing phrase's wordlist and checksum validity.
FAQ
Is this compatible with cryptocurrency wallet recovery phrases?
Yes. It uses the official 2048-word BIP39 English wordlist and computes the correct checksum, so every phrase it generates is a standards-compliant BIP39 mnemonic - the same format used by hardware and software wallets.
Should I use this to create the seed phrase for a wallet holding real funds?
Prefer generating it directly on the wallet's own offline or hardware device. Nothing you generate here is ever transmitted, logged, or stored - it all happens locally in your browser - but any internet-connected device carries more risk than an air-gapped one.
How random are the generated words?
Entropy comes from the browser's cryptographically secure random number generator (crypto.getRandomValues), not Math.random(). The mnemonic's last bits are a SHA-256 checksum of that entropy, exactly as BIP39 specifies.
Can I choose how many words are generated?
Yes - 12, 15, 18, 21, or 24 words, corresponding to 128, 160, 192, 224, and 256 bits of entropy, the five lengths BIP39 defines.
Can I check whether an existing phrase is valid?
Yes - switch to the Verify tab and paste it in. Each word is checked against the wordlist and the full phrase against its BIP39 checksum, instantly and locally, so you can catch a typo or a wrong word order before it matters.
What's the difference between a 12-word and a 24-word seed phrase?
It's entropy, not extra security features - 12 words encode 128 bits of entropy and 24 words encode 256 bits, per the BIP39 spec. Both are considered cryptographically secure for practical use; 24 words simply gives a larger security margin, which is why some wallets default to it.
Does this work for Ethereum, Solana, or other non-Bitcoin wallets, not just Bitcoin?
Yes - BIP39 mnemonics are a chain-agnostic standard used by Bitcoin, Ethereum, Solana, and most other major wallets. This tool generates and verifies the mnemonic itself; it doesn't compute chain-specific derivation paths, addresses, or keys, so it pairs with whichever wallet you're using regardless of chain.
How we compare
| Feature | Online Tool Store | ianColeman-style BIP39 tools | Random password generator |
|---|---|---|---|
| Official BIP39 wordlist + checksum | ✓ | ✓ | ✗ |
| Built-in phrase verification | ✓ | ✓ | N/A |
| No derivation paths, addresses, or private keys shown | ✓ | ✗ | N/A |
| Mask/reveal toggle for shoulder-surfing safety | ✓ | Sometimes | ✗ |
| Runs entirely offline in your browser | ✓ | Usually | Usually |
Use this when you want a clean, standards-correct BIP39 phrase or a quick validity check, without the clutter and larger attack surface of a full multi-coin derivation tool.