BIP39 Seed Phrase Validator — Check Wallet Recovery Words Offline
Check whether individual words in a seed phrase appear in the official BIP39 English wordlist — useful when recovering a wallet and suspecting a typo. Shows word-by-word results for 12- or 24-word phrases. Runs in your browser: no words are ever transmitted. Never enter a real seed phrase on any website.
How to use this tool
- Enter a 12- or 24-word seed phrase with words separated by spaces.
- Each word is checked against the official BIP39 English wordlist.
- See word-by-word results — valid words in green, invalid in red.
BIP39 is a standard for encoding entropy as a mnemonic phrase of 12 or 24 words. This tool validates:
- Word count (must be 12 or 24)
- Each word is in the official BIP39 English wordlist
- Checksum validation using SHA256
- Fuzzy matching suggestions for misspelled words
About BIP39 Seed Phrase Validator
BIP39 is the standard most wallets use to turn a string of random entropy into a human-friendly mnemonic, a sequence of common English words drawn from a fixed list of 2,048 entries. This tool checks a seed phrase against that standard so you can catch the most common recovery problem: a mistyped or misremembered word. You paste a phrase, words separated by spaces, and the tool inspects it as you type, after a brief pause, marking each word green if it appears in the official BIP39 English wordlist and red if it does not.
Two checks run on every phrase. The first is length: BIP39 phrases are valid only at specific word counts, and this tool treats the two most common lengths, 12 and 24 words, as the valid targets, flagging anything else as the wrong length. The second is wordlist membership, where each word is looked up in the 2,048-word list. When a word is not found, the validator computes the edit distance between what you typed and every word in the list and offers up to three close matches as clickable suggestions, so a transposed letter or a single typo like abandom for abandon is easy to spot and fix with one click.
The single most important rule for a tool like this is to never type a real seed phrase into any website, including this one, and the page leads with that warning in red. A seed phrase is the master key to a wallet; anything that reaches a web page should be considered exposed, even when, as here, the processing happens locally. Use the validator with practice phrases, test vectors, or a phrase you are reconstructing from a backup that no longer controls funds. If you ever enter a live phrase anywhere online, move the funds immediately.
It is worth being clear about what this tool does and does not prove. It reliably confirms word count and that every word belongs to the BIP39 list, and it gives spelling suggestions, which together catch the great majority of recovery typos. It is not a substitute for the full cryptographic checksum verification and key derivation that your wallet software performs when you actually restore from a phrase. Treat a green result as a strong sign the words and length are right, then let your wallet do the authoritative recovery. All checking happens in your browser; no words are transmitted.
Frequently Asked Questions
- What is BIP39?
- BIP39 is a Bitcoin Improvement Proposal that defines how to encode wallet entropy as a mnemonic seed phrase using a standardized list of 2,048 English words. The vast majority of hardware and software wallets implement BIP39, which is why a phrase generated by one wallet can often be restored in another.
- Why does it only accept 12 or 24 words?
- BIP39 supports several lengths, but 12 and 24 words are by far the most common and are what this tool treats as valid. A 12-word phrase encodes 128 bits of entropy plus a 4-bit checksum, and a 24-word phrase encodes 256 bits plus an 8-bit checksum. Other lengths exist in the standard but are rarely used by wallets.
- What do the suggestions do?
- When a word is not in the BIP39 list, the validator measures how many single-character edits separate it from each list word and offers the closest matches, up to three, as clickable buttons. This catches typos such as a swapped or missing letter. Clicking a suggestion replaces the bad word in your phrase so you can re-check instantly.
- Does a green result mean my phrase is definitely valid?
- It means every word is spelled correctly and present in the BIP39 wordlist and that you have a 12- or 24-word phrase. That catches almost all transcription errors. It is not the same as the full checksum verification and key derivation your wallet performs during an actual restore, so use a green result as strong confirmation of the words and length, then recover authoritatively in your wallet.
- Is it safe to type a real seed phrase here?
- No. You should never enter a real, fund-controlling seed phrase into any website, this one included. Although the checking runs locally in your browser, treating any phrase you type online as potentially exposed is the only safe assumption. Use the tool with test phrases or phrases that no longer guard real assets.
- Are the words sent to a server?
- No. The wordlist lookup, the length check, and the typo suggestions all run in your browser. The words you enter are never transmitted, logged, or stored.
- Can I recover my wallet with this tool?
- No. This validator only checks the spelling, wordlist membership, and length of a phrase. It does not derive keys, addresses, or balances. Actual wallet recovery, including the cryptographic checksum and key derivation, is done inside wallet software, which is where you should restore.
- Why is my correctly spelled phrase still flagged?
- The most common reasons are an incorrect word count, extra spaces creating empty entries, or a word that looks right but is not actually in the BIP39 list, since the list contains specific spellings. Check that you have exactly 12 or 24 words and that each appears in green. The BIP39 list uses American English spellings, which occasionally differ from what you might expect.
Embed this tool on your site
Free. One line of HTML — the tool runs in your visitor's browser, no data sent to anyone.
<iframe src="https://brevio.pro/embed/bip39-validator" width="100%" height="600" loading="lazy" style="border:1px solid #e5e5e5;border-radius:8px" title="BIP39 Seed Phrase Validator — brevio"></iframe> <p style="font:12px/1.4 sans-serif"><a href="https://brevio.pro/tools/bip39-validator">BIP39 Seed Phrase Validator</a> by <a href="https://brevio.pro">brevio</a></p>