11 of 12 Words: Can a Partial Seed Phrase Be Recovered?

field_notes // partial_seed_math

Short answer: yes, and often faster than you think. Here is the long answer.

The math of a missing word

BIP-39 uses a 2048-word wordlist. Your recovery phrase is drawn from that list. The final word contains a checksum — meaning only 1 in every 16 (for 12-word phrases) or 1 in 256 (for 24-word phrases) random combinations passes validation.

If exactly one word is unknown, the search space is 2048 candidates. Of those, roughly 128 (for 12-word) or 8 (for 24-word) pass the checksum. Each valid candidate is turned into a master key, from which we derive a wallet address and compare to a target you provide.

On a modern GPU, this entire process finishes in seconds. Yes, seconds — assuming you know the derivation path.

Two missing words

Search space: 2048 × 2048 = ~4.2 million. After checksum filter: ~260,000 candidates for a 12-word phrase. Each candidate requires an HD-wallet derivation and address check. Realistic timeline: minutes to hours on a single GPU.

Three missing words

Search space: 2048^3 = ~8.6 billion. After checksum filter: ~537 million candidates. Realistic timeline: hours to a few days on a GPU cluster.

Four missing words

Search space: 2048^4 = ~17.6 trillion. After checksum filter: ~1.1 trillion candidates. Realistic timeline: weeks on serious hardware. Case-by-case only.

Beyond four

The search space grows geometrically. At five unknowns you're looking at trillions of candidates even after filtering, and the compute cost usually exceeds the potential recovery value unless the wallet is worth six figures or more. We'll be honest with you on the assessment call.

The variables that change everything

Position hints. If you know word 4 is missing (vs. "some word is missing but I don't know which"), the search space collapses dramatically.

Approximate letters. If you remember "it started with 'a' and was short," the candidate list drops from 2048 to maybe 40. That's a 50x speedup.

The derivation path. BIP-44 (legacy Bitcoin), BIP-49 (P2SH), BIP-84 (native SegWit), BIP-86 (Taproot), and Ethereum's own path all produce different addresses from the same seed. If you don't know which wallet software generated the phrase, we may need to test multiple paths, multiplying compute cost.

The target address. Without one, none of this is possible. We need one known good address from that wallet to validate candidates against. If you don't have one, and can't dig one up from a block explorer using an old transaction, recovery is off the table.

The passphrase (25th word). If you used a BIP-39 passphrase in addition to the standard phrase, we need to recover it separately — see our password recovery guide. A missing word plus a missing passphrase is two search spaces multiplied.

Common damaged-backup scenarios we handle

Fire-damaged paper backups — often partial words visible, we work from the fragments.
Faded ink — position-mapped partial recovery. We frequently get single missing chars per word.
Cryptosteel or metal plate corrosion — same approach.
Photo compressed too much — pixel-level analysis + candidate matching.
Two backups that disagree — cross-reference and test both.
Handwriting you can't read your own of — you'd be surprised how often this is the case.

What we need from you

The words you can identify, in their positions (or approximate positions).
Any partial letters, guesses, or fragments for unknown words.
One address from that wallet.
The wallet software that generated the phrase.
Whether a passphrase was used (yes/no is enough for the initial assessment).

That's it. We never ask for the full seed phrase, because obviously — if you had it, you wouldn't need us.

The workflow

Free assessment — you send the info above via encrypted channel.
We compute the feasible search space and timeline.
We quote a success fee. No fee if we recover nothing.
On approval, we run the search.
On success, we deliver the missing word(s) to you securely. You reconstruct the phrase, restore the wallet on your device, and move your own funds.

We never touch your funds. We deliver the missing information; you regain control.

FAQ

How fast is single-word recovery? Seconds to minutes, given a target address and correct derivation path.

Do you work with 18-word phrases? Yes. Some old Electrum and Trezor setups used 18-word phrases; math is the same.

What if I only remember 6 of 12 words? Feasibility depends on which 6 and how much other info you can provide. We'll assess.

Is any of this legal? Recovering your own wallet with the wallet's owner's permission — yes, everywhere. We do not attempt anyone else's wallet.

Cost? Free assessment. Success-only, typically 15–20% of recovered assets. No recovery, no fee.

Free assessment. Never asks for the full phrase. No recovery, no fee.