Measured in centuries
BROWSER-LOCAL COMPUTATIONBitcoin only English BIP39
YOUR BITCOIN SEED, EXPLAINED.
Understand the strength
behind your seed.
From recovery words to risk, randomness, and Bitcoin addresses.
A private, browser-local workspace for learning how it all fits together.
No accountsNo data uploadsWorks offline
01 / THE PHRASE
Start with words or bits.
Paste a test phrase, import raw binary entropy, or explore with a generated example.
Explore a fresh seed.
Create a test phrase and explore its words, entropy, and Bitcoin addresses.
Browser-generated randomness. Analyzed automatically.
Your generated phrase
Explore your words.
Check the format and recognized weaknesses of an existing phrase.
0 words
Enter a phrase to check its structure.
English letters and spaces only · 12, 15, 18, 21, or 24 words. All calculations happen in this page.
Begin with the bits.
Turn your binary entropy into recovery words.
Enter 128, 160, 192, 224, or 256 bits for 12, 15, 18, 21, or 24 words. Type only 0 and 1. Spaces and line breaks in pasted bits are removed. Enter entropy only: the BIP39 checksum is added automatically. Leading zeros are preserved.
Enter binary entropy to create a phrase.
Your seed phrase
CURRENT PHRASE
What we can tell you
A format check. A search for known weaknesses.
THE FINDING
Analyze a phrase to see its risk
Why this result?
Waiting for a phrase
Enter words to check their length, wordlist, and checksum.
Encoded entropyN/A bits
Capacity for randomness
ChecksumN/A bits
Helps detect input errors
What this cannot prove
That your words were chosen randomly or that only you know them. Bit length describes capacity, not measured security.
Generation source & check limits
Origin unverified
We check public test phrases and a limited set of simple patterns. Other weaknesses can go undetected.
Your assessment, entropy details, and address tools will appear after a valid phrase is analyzed.
Entropy details Explore the numbers behind your words →
Every word represents a number.
The English BIP39 list contains 2,048 words, indexed from 0 to 2047. Each index becomes 11 binary digits. Together, those digits encode the entropy and its checksum.
Index 0 = abandon.
The official word list on GitHub ↗ displays lines starting at 1. To find a word there, add 1 to its BIP39 index: index 1477 → line 1478. “Word 1” below means the first word in your phrase, not its wordlist index.
Analyze a valid phrase to see its word indices.
These numbers and binary digits reveal the same secret as the recovery phrase. Treat them with the same care.
Entropy
HEXADECIMAL
No valid phrase loaded.RAW BINARY · ENTROPY BITS ONLY
No valid phrase loaded.Checksum & full encoding
CHECKSUM BITS · NOT ADDITIONAL ENTROPY
No valid phrase loaded.FULL MNEMONIC BINARY · ENTROPY + CHECKSUM
No valid phrase loaded.Structure checks
- Word count
- Waiting
- English wordlist
- Waiting
- Checksum
- Waiting
Pattern checks
These checks recognize a limited set of simple constructions. Passing them cannot certify a generator or establish secrecy. The checksum detects some mistakes; it does not add randomness.
02 / THE POSSIBILITIES
How hard is this phrase to guess?
A simple picture of the result. Valid words alone cannot prove randomness or secrecy.
Actual source entropy
Not analyzed
Picture it simply
Estimated guessing effort
Conditional estimateAverage search time
Analyze a phrase first
Explore the calculation and compare lengths
For comparison only. These are complete seed checks, not Bitcoin mining hashes.
Chance after 100 years
Assumptions and limits
Estimates need a stated generation or attack model, a known verification target, and a fixed or known passphrase.
This describes phrase guessing only. Exposure, a predictable generator, malware, partial knowledge, and other attacks can bypass this model. Checksum bits and the derived 512-bit seed do not add randomness.
The calculation
Displayed times are rounded to three significant digits. The average assumes no repeated guesses and an equally likely target position. A family-size upper bound gives an upper bound on that model’s average. Checking rates are illustrations, not measured hardware performance. Choosing a faster rate does not change the phrase or its risk finding.
Compare other phrase lengths
Hypothetical comparison only. These figures do not assess the phrase above. They assume uniformly random generation, a fixed or known passphrase, and a known verification target. Checking rates are illustrations, not hardware benchmarks or mining hash rates.
Possible phrases
3.40 × 10³⁸
128 random bitsAverage exhaustive search
5.39 × 10¹⁸ years
Half the space, on averageGuess every flip.
Imagine guessing the exact outcome of 128 independent, fair coin flips. All of them, in order. That’s the chance of one correct guess.
Pick one ticket.
A lottery with one winner among 3.40 × 10³⁸ equally likely tickets. Each extra random bit doubles the number of tickets.
Exact numbers for this comparison
- Possible phrases · N = 2ᴱᴺᵀ
- Probability of one correct guess
- Average search · (N + 1) / (2R)
Assumes uniform random generation, no repeated guesses, a fixed or known passphrase, and a known target to verify each candidate. One year is 31,557,600 seconds. Checking rates are illustrations, not measured hardware performance or Bitcoin mining hash rates.
This models searching for a phrase. It does not measure overall wallet security, other attacks on Bitcoin keys, malware, or exposure. A 512-bit derived seed and checksum bits do not create extra randomness. Unknown or human-chosen generation may have a much smaller search space.
03 / THE BITCOIN PATHS
One seed. Different destinations.
A derivation path tells a wallet which keys to use. These are common conventions; the words alone don’t identify which path your wallet used.
Choose an address type above. Path examples show mainnet, account 0, receiving address 0. An apostrophe marks hardened derivation. Testnet uses coin type 1'.
Case and spaces matter. Every passphrase creates a different wallet; there’s no “incorrect passphrase” error. Unicode is normalized with NFKD.
Enter a valid phrase above to derive addresses.
Derived addresses
| Index | Derivation path | Bitcoin address | Copy |
|---|
TAKE IT OFFLINE
Same tool.
No connection required.
One HTML file, with everything included. No installation, accounts, or external libraries to load.
Download offline HTML- Download and verify.Get the file and SHA256SUMS from a trusted release. Compare its SHA-256 hash; rebuild from the pinned source for additional verification.
- Move to a trusted, disconnected device.Transfer the verified file to your offline computer. Browser extensions, malware, and operating-system security still matter.
- Open it in your browser.Double-click the HTML file. A local-file label does not prove an air gap. Clear the session and close the page when finished; browser memory erasure cannot be guaranteed.
Standards, dependencies & limitations
Based on BIP39, BIP32, BIP44, BIP49, BIP84, and BIP86. Statistical tests cannot certify a cryptographic generator: NIST SP 800-22. Checksum validity does not establish randomness or secrecy.
English BIP39 only. Other formats, including native Electrum and SLIP39 phrases, are not assessed. This tool does not find balances, recover missing words, or sign transactions. It stores no session data and makes no runtime network requests. Following an external link or downloading from the hosted page is an explicit network action.
Cryptography uses @scure/bip39, @scure/bip32, and @scure/btc-signer. Dependency audit history is not an audit of this application. SeedInspect has not received an independent security audit.
Open-source license notices
SeedInspect 1.0.0 MIT License Copyright (c) 2026 SeedInspect contributors Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. Public BIP39 examples: trezor/python-mnemonic The MIT License (MIT) Copyright (c) 2013-2016 Pavol Rusnak Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. Bundled dependency licenses @noble/curves@2.4.0 ================================================================ The MIT License (MIT) Copyright (c) 2022 Paul Miller (https://paulmillr.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. @noble/hashes@2.4.0 ================================================================ The MIT License (MIT) Copyright (c) 2022 Paul Miller (https://paulmillr.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. @scure/base@2.4.0 ================================================================ The MIT License (MIT) Copyright (c) 2022 Paul Miller (https://paulmillr.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. @scure/bip32@2.4.0 ================================================================ The MIT License (MIT) Copyright (c) 2022 Patricio Palladino, Paul Miller (paulmillr.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. @scure/bip39@2.4.0 ================================================================ The MIT License (MIT) Copyright (c) 2022 Patricio Palladino, Paul Miller (paulmillr.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. @scure/btc-signer@2.4.1 ================================================================ The MIT License (MIT) Copyright (c) 2022 Paul Miller (https://paulmillr.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. micro-packed@0.11.1 ================================================================ The MIT License (MIT) Copyright (c) 2022 Paul Miller (https://paulmillr.com) Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.