Almost every other cryptocurrency settled on one seed format and moved on. Monero has four in active use, and if you have ever pasted a perfectly valid seed into a perfectly good wallet and been told it is invalid, you have run into the consequences.
The confusion is not your fault. The formats look similar — a list of ordinary English words — but they encode different amounts of information in incompatible ways. This guide explains what each format is, how to recognise which one you are holding, and the one rule that prevents the worst mistake people make with them.
Why four formats exist at all
Each format was created to solve a problem the previous one had.
The 25-word seed is Monero's original and canonical format. It encodes your private spend key directly, in full.
The 13-word seed came from MyMonero, which wanted something shorter and more memorable for a light wallet aimed at everyday users.
BIP-39 is the industry-standard format used by Bitcoin, Ethereum and essentially every hardware wallet. Monero tooling grew support for it largely so hardware wallets and multi-coin wallets could manage Monero alongside everything else.
Polyseed is the modern answer, designed specifically for Monero to fix a genuine and irritating flaw in all three of the others: none of them record when the wallet was created, which is why restoring an old wallet means guessing a block height and waiting.
The 25-word standard seed
This is the format the official Monero GUI and CLI produce by default, and the one most people mean when they say "my Monero seed".
Twenty-four of the words encode your private spend key — 256 bits of it — and the twenty-fifth is a checksum. That checksum is genuinely useful: it means a wallet can tell you that you mistyped a word rather than silently opening an empty wallet at a completely different address.
The words come from a Monero-specific list of 1,626 words, and critically, it is not the same wordlist BIP-39 uses. This is the single fastest way to identify what you are holding. Monero's list contains words BIP-39 does not, and only the first few letters of each word matter for decoding, which is why the list contains entries that look like fragments.
Standard seeds exist in several languages — English, Spanish, German, Japanese and others. A seed generated with the Spanish wordlist will not restore in a wallet set to English, which is an occasional and very confusing source of "invalid seed" errors.
The MyMonero 13-word seed
Shorter, and specific to MyMonero and the light wallets built in its lineage. Twelve words encode 128 bits of entropy, and the thirteenth is a checksum.
The reduced entropy is worth understanding but not worth panicking about: 128 bits remains far beyond any brute-force capability that exists or is projected to exist. The practical difference is compatibility, not security. Many wallets simply do not implement the 13-word format, so a valid seed can be rejected by a perfectly good wallet that only speaks 25-word.
If you are migrating away from MyMonero, this is the detail that matters most, and we cover the process in our MyMonero migration guide.
Polyseed — the one that fixes restore heights
Polyseed is sixteen words, and it is the most interesting of the four because it carries more than just a key.
Alongside 128 bits of entropy, a Polyseed encodes the approximate date the wallet was created, plus a small set of feature bits for forward compatibility, plus a checksum. That embedded creation date is the whole point: a wallet restoring from a Polyseed already knows roughly where to start scanning, so it can skip years of irrelevant blocks without asking you to remember anything.
If you have ever restored an old wallet, watched it scan for forty minutes, and then discovered your balance was wrong because you guessed the restore height badly, you already understand why this matters.
Polyseed also handles multiple languages properly and was designed with future changes in mind rather than bolted on. For a newly created Monero wallet, it is the format we would recommend — with one caveat: it is newer, so support is not yet universal. Check that the wallets you intend to use actually accept it before committing to it as your only backup.
BIP-39
BIP-39 is the twelve-or-twenty-four-word format you have seen everywhere else in crypto. Its role in Monero is essentially interoperability: hardware wallets and multi-coin wallets already speak BIP-39, so supporting it lets those tools manage Monero without inventing something new.
The important caveat is that BIP-39 in Monero is not standardised the way it is in Bitcoin. Different tools have historically derived Monero keys from BIP-39 entropy in different ways. In practice this means a BIP-39 seed that produces one address in wallet A may produce a different address in wallet B.
This is not a theoretical concern. It is the most common cause of the "my funds are missing" panic that turns out to be "my funds are in a different wallet than the one I am looking at". If you use BIP-39 with Monero, record which wallet or derivation you used alongside the seed itself. The words alone may not be enough information to get back to the right address.
The address is the source of truth. Whatever format you restore, always confirm the resulting address matches the one you expect. A wallet that opens successfully at the wrong address will show a zero balance and look exactly like theft. It usually is not theft — it is a derivation mismatch.
Which format should you use?
| Your situation | Use |
|---|---|
| Creating a new wallet today | Polyseed, if your wallets support it |
| Want maximum compatibility | 25-word standard |
| Using a hardware wallet | BIP-39 (record the derivation) |
| Migrating off MyMonero | Keep your 13-word seed; do not try to convert it |
| Managing several coins in one app | BIP-39 |
For most people creating a fresh Monero wallet, the honest ranking is: Polyseed if supported, 25-word otherwise. Both are Monero-native, both have real checksums, and neither carries BIP-39's derivation ambiguity.
The rule that prevents the worst mistake
Here is the one thing to take away from this article:
You cannot convert a seed from one format to another and keep the same wallet. These formats are not different spellings of the same secret. They use different entropy sizes and different derivation paths. Feeding your 25-word seed into a Polyseed generator does not "upgrade" your wallet — it creates a completely new and unrelated one.
People discover this the expensive way. The sequence goes: read that Polyseed is better, "convert" the seed, get a new address, send funds to it, throw away the old seed because the new one is "the same wallet". It is not. The old seed controlled the old address, and if you discarded it, those funds are gone permanently.
If you genuinely want to move to a different seed format, the only correct procedure is a real transaction:
- Create a brand-new wallet using the format you want.
- Write down and verify the new seed.
- Send your funds from the old wallet to the new wallet's address, on-chain.
- Wait for confirmations and verify the balance arrived.
- Keep the old seed anyway, at least for a while. It costs nothing.
Recognising which format you hold
A quick field guide:
- 12 or 24 words → BIP-39.
- 13 words → MyMonero light-wallet format.
- 16 words → Polyseed.
- 25 words → Monero standard.
If the count is ambiguous, look at the words themselves. BIP-39 uses only complete, ordinary English words from a fixed 2,048-word list. Monero's list contains truncated-looking entries that are clearly not standard dictionary words. Seeing one of those means you are not holding a BIP-39 seed.
Storing seeds sensibly
Independent of format, the storage rules do not change:
- Write it on paper or stamp it into metal. Not a screenshot, not a cloud note, not an email to yourself.
- Never type a seed into a search bar. It happens more than you would think.
- Store a second copy somewhere geographically separate. Fire and flood are more common causes of loss than theft.
- Record the format and the wallet you used, especially for BIP-39. Future you will not remember.
- Never share it. No support agent, developer or "recovery service" ever needs it. Every single request for your seed is an attempted theft.
Our wallet detects all four formats automatically — you paste the words and it works out which one you have — but that convenience does not change any of the advice above. The seed is the wallet. The software is just a lens.