Bitaigen Research 
In this article we systematically outline the response strategies after a mnemonic phrase is lost, providing detailed evaluations of recovery tools such as Seed Saviour and Btcrecover, explaining their underlying principles and usage workflows. We also demonstrate, through real‑world examples, how a brute‑force search can be employed to retrieve assets when only a subset of the words is remembered. For a complete understanding of feasibility and practical steps, we recommend reading the full text.
What to Do When a Crypto Wallet’s Mnemonic Phrase Is Lost?
If the mnemonic phrase of a crypto wallet is lost, you can combine the subset of words you still remember with tools like Seed Saviour or Btcrecover to conduct a brute‑force search, recover the missing words, and restore access to the assets.
Background of the Incident
A short while ago I came across a plea on a social platform: a user had written down several words incorrectly during backup, resulting in only a partial recollection of the wallet’s mnemonic phrase while the remaining words were completely lost. This raised a critical question: is it still possible to recover the entire wallet when only part of the phrase is remembered?
Theoretical Feasibility of Brute‑Force Cracking
A mnemonic phrase typically consists of 12 words. According to the BIP‑39 standard, all 12 words are drawn from a fixed list of 2 048 possible words. In theory, the missing words can be recovered by exhaustively enumerating every possible combination. The table below shows the number of possible combinations and the estimated time required on an average personal computer, based on the count of missing words (see the accompanying chart
):
| Number of Missing Words | Combination Count (2048ⁿ) | Estimated Time on a Typical PC |
|---|---|---|
| 1 | 2 048 | roughly 6 seconds |
| 2 | 4 194 304 | roughly 90 seconds |
| 3 | 8 589 934 592 | roughly 2 days |
| 4 | 17 592 186 044 416 | roughly 10 years |
From the table it is evident that when no more than three words are missing, a search using ordinary computing hardware can still be completed within a tolerable timeframe; missing four or more words makes the task practically impossible.
For a more detailed calculation process, refer to the diagram
. If you still remember at least three‑quarters of the 12‑word phrase (i.e., 9 words or more), the probability of successful recovery is relatively high.
Common Recovery Tools
After extensive research, I selected two user‑friendly recovery utilities that cater to different loss scenarios.
1. Seed Saviour (Ideal for a Single Missing Word)
Seed Saviour is a browser‑based mnemonic recovery tool that is straightforward to operate. The procedure is as follows:
- Visit the Seed Saviour web page (see reference [1] at the end of the article).
- Paste the portion of the mnemonic phrase you still remember into the input field.
- Replace each missing word with a “?” and indicate its exact position (the order must be correct).
- After a brief pause, the tool will display every possible word together with the corresponding address.
⚠️ This tool only supports scenarios where one word is missing. A screenshot of the interface is shown here: !Command‑line interface of the Btcrecover recovery tool.
2. Btcrecover (Suitable for Two or More Missing Words)
Btcrecover is an open‑source password‑recovery script that supports multiple blockchains (including Ethereum EVM and non‑EVM chains), making it appropriate for more complex cases where several words are missing or the address is unknown. The basic workflow is:
- Download and extract the Btcrecover scripts from GitHub (reference [2]).
- Install Python 3 on your system.
- In a terminal, run `pip install -r requirements.txt` to install the required dependencies.
- Open a command prompt, navigate to the directory containing the scripts, and execute `python seedrecover.py`. An interactive interface will appear, first asking you to choose the wallet type (e.g., ETH).
- After selecting the wallet type, you may either provide a public key or skip that step. Then paste the wallet address (if you remember it) and proceed to the next step.
- In the “seed phrase” field, again use “?” to represent each missing word while preserving the original order. Once confirmed, the script will begin enumerating the missing words and will compare each generated address with the one you supplied in the previous step.
- When a match is found, the system will reveal the complete mnemonic phrase. In my own testing, recovering a phrase with two missing words took roughly two minutes.
Security Reminder: After a successful recovery, immediately transfer the assets to a new, securely stored wallet to mitigate any further risk.
Re‑Evaluating Wallet Security
Many users worry that if a mnemonic phrase can be brute‑forced, hackers might also retrieve it with ease. The reality is that under normal circumstances, the probability of an attacker correctly guessing all 12 words is virtually zero.
The total number of possible 12‑word combinations is 2048¹², which equals approximately 3.4 × 10³⁸ possibilities (as shown earlier). Even with massive computational power, it is infeasible to try every combination within any reasonable timeframe. Only if the user voluntarily leaks the full mnemonic phrase—for example, by storing it on an insecure device or cloud service—or if the device is compromised by malware that exfiltrates the phrase, would the wallet be at real risk.
Summary
This article provides a systematic overview of the strategies and practical tools for recovering a lost mnemonic phrase:
- Seed Saviour: Fast recovery when a single word is missing.
- Btcrecover: Advanced recovery supporting multiple missing words and address verification.
Please note that this material is intended solely for educational and informational purposes; it must not be used for illicit activities. If you manage to restore your mnemonic, be sure to move the funds to a brand‑new wallet and back up the new phrase securely.
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Acknowledgements: Axel_bitblaze69, 0xTHades, Senka (cover design)
Disclaimer: The opinions expressed herein reflect personal analysis and do not constitute investment advice. Cryptocurrency assets carry risk; please act responsibly and comply with the laws and regulations of your jurisdiction.
References
[1] https://3rditeration.github.io/mnemonic-recovery/src/index.html
[2] https://btcrecover.readthedocs.io/en/latest/INSTALL/
Related Reading
- Private Key, Mnemonic Phrase & Keystore Passwords
- How to Create or Import a Polkadot (DOT) Wallet with TP Wallet
- Secure Your Blockchain Wallet: Private Keys & Seed Phrases
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