Last updated: October 21, 2026
A BIP-39 passphrase — often called the "25th word" — is an optional extra password added to your seed phrase that creates a completely different wallet: the same 12 or 24 words with a different passphrase open a different set of addresses, so someone who finds your seed alone can't reach the funds behind the passphrase. It protects against a stolen seed backup and enables a decoy wallet, but if you forget the passphrase, those funds are lost forever. Here's how to use it safely on a hardware wallet holding coins from swaps like BTC → XMR.
- 12/24 seed words + 1 passphrase
- Every passphrase = a different wallet
- 0 ways to recover a forgotten one
- Decoy wallet built in
How the passphrase works
Your seed words and the passphrase are combined to derive the wallet's keys. Change one character of the passphrase and you get a different, valid, empty-looking wallet — there is no "wrong passphrase" error. That's the point: an attacker can't tell whether a passphrase exists or which wallet is the real one.
Seed only vs seed + passphrase at a glance
| Seed only | Seed + passphrase | |
|---|---|---|
| Someone finds your seed backup | They take everything | They see only the no-passphrase wallet |
| Decoy wallet under coercion | Not possible | Reveal the seed-only wallet with a small balance |
| Recovery needs | Seed | Seed + exact passphrase |
| Risk of self-lockout | Low | Higher — a typo or forgotten passphrase loses funds |
How to set up a passphrase safely (step by step)
- Back up your seed first and test it — see seed backup for the general rules.
- Choose a strong but memorable passphrase; spaces, case and symbols all matter.
- Enable it on your hardware wallet (most support it) and note the first receive address it shows.
- Store the passphrase separately from the seed — never on the same paper or plate.
- Test recovery: restore on a spare device with seed + passphrase and confirm the same first address.
- Keep a small amount in the no-passphrase wallet as a decoy — useful against wrench attacks.
Passphrase and Monero
BIP-39 passphrases are a Bitcoin/EVM wallet standard. Monero uses its own seed formats: classic 25-word seeds have no standard passphrase, while newer Polyseed seeds support an optional seed passphrase in wallets that implement it, and hardware wallets can protect Monero accounts with their device passphrase. Check your wallet's documentation — see best Monero wallets.
Common mistakes
- Forgetting the exact passphrase — including capitalization or a trailing space.
- Storing seed and passphrase together — that defeats the purpose.
- Not telling your heirs — plan for it in your inheritance plan.
- Typing it into websites — no exchange or support team ever needs it; see fake exchanges.
Frequently asked questions
What is the 25th word in crypto?
An optional BIP-39 passphrase added to your 12 or 24 seed words. It creates a separate wallet that can't be accessed with the seed alone.
What happens if I enter the wrong passphrase?
You open a different, empty wallet without any error. Funds aren't lost, but you need the exact passphrase to see them.
Can a forgotten passphrase be recovered?
No. Without the exact passphrase the funds are inaccessible. That's why you test recovery and store it safely, separately from the seed.
Should beginners use a passphrase?
Only once they're comfortable with seed backups and recovery. For many beginners, a well-protected seed alone is safer than an untested passphrase.
Does a passphrase make my transactions private?
No. It protects access to your keys, not on-chain privacy. For privacy, hold value in Monero — see Monero vs Bitcoin.
Protect what you swap in: BTC → XMR, USDT → BTC or why self-custody matters. No account, no ID, no logs.