How to Store a Seed Phrase
A seed phrase is the 12- or 24-word master backup from which all of a crypto wallet’s private keys are derived. Anyone who has it can restore your wallet, so it needs to be stored offline and securely.
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A seed phrase, also called a recovery phrase, is the master backup, usually 12 or 24 words, from which every private key in your crypto wallet is derived. If your phone is lost or your hardware wallet breaks, those words let you restore the exact same wallet on another device. For the same reason, anyone who sees them can spend your funds without ever touching your device.
That makes how you store your seed phrase at least as important as which wallet you choose. Whether you use a mobile app or a hardware wallet, the device can be replaced; the words cannot. Below we explain how the words work, compare storage options and cover the mistakes that cost people the most.
How does a seed phrase work?
Most wallets follow a standard called BIP-39. It defines a fixed list of 2,048 words, and during setup the wallet turns a randomly generated number into a sequence of words from that list. Twelve words encode 128 bits of randomness and 24 words encode 256 bits; both are far beyond what anyone could guess by brute force.
The last word includes a checksum calculated from the others, so if you mistype a word, the wallet will usually reject the phrase as invalid. In the English list, every word is uniquely identified by its first four letters, which makes getting those letters right especially important.
A single seed phrase can generate hundreds of addresses across Bitcoin, Ethereum and other networks. If a balance doesn’t show up after restoring, the new app is probably using a different derivation path.
How to store a seed phrase, step by step
- Only use words generated by your device. Write down the words your wallet creates during setup. Never use a phrase supplied by a website, a seller or a card in the box.
- Write them down numbered and complete. Record each word with its position, legibly and correctly spelled. Order is part of the key: the same words in a different order are a different wallet.
- Don’t make digital copies. Screenshots, phone notes, email drafts, cloud photos and password managers all tie your phrase to the security of an online account.
- Choose a durable medium. Paper can be ruined by water or fire. For larger amounts, stamping or engraving the words onto a stainless steel plate is a common solution.
- Test the backup. Use your device’s built-in backup check, or wipe and restore while holding only a small balance. Never type the words into a website to “verify” them.
Seed phrase storage options compared
- Paper: cheap and simple, but vulnerable to water, fire and being thrown away. Fine for small to moderate amounts.
- Metal plate: survives fire and flooding and is the most common choice for long-term savings. Who can see it matters just as much as with paper.
- Copies in two locations: reduces the risk of loss but increases the risk of exposure. Each location’s security has to be considered on its own.
- Split backups: cutting the words into two halves yourself is a bad idea, because whoever finds one half is far closer to guessing the rest. If you want a split backup, use a standard scheme such as Shamir backup (SLIP-39) or a multisig setup.
Inventing your own cipher to “hide” the words is risky too. Years later you may not remember how it works, and a family member almost certainly won’t.
What to know if you use a passphrase
Some wallets let you add an optional passphrase, sometimes called the 25th word, to your seed phrase. The passphrase opens a separate wallet, so someone who finds your words still can’t reach the real balance without it. The catch: forget the passphrase and the words alone won’t restore that wallet.
Storing the passphrase alongside the words cancels out the protection, while storing it somewhere completely separate raises the risk of losing it. Work out that balance before relying on a passphrase for significant amounts.
Seed phrase mistakes to avoid
- Typing your words into a support chat, a “wallet validation” site or an airdrop form. Any request for your seed phrase is phishing.
- Photographing the words and sending them to yourself on a messaging app.
- Guessing a word you can’t read, or rearranging the words alphabetically.
- Entering the words into an unfamiliar app just to test a restore.
What to do if your seed phrase is compromised
If you suspect someone has seen your words, act immediately. Create a brand-new wallet with a new seed phrase on a secure device, then move your funds on-chain to the new address. Changing the old wallet’s password or PIN doesn’t help: anyone with the words can open the wallet on their own device.
Move the most valuable and most easily transferable assets first. If anything is staked or locked at the old address, move it as soon as you can. After that, stop using the old wallet entirely.
Long-term access and inheritance
A seed phrase isn’t only about security today; it’s about access years from now. If your family doesn’t know which device and backup control which assets, those assets can become permanently unreachable.
A simple approach is an instruction letter that doesn’t contain the words themselves: which wallet you use, where the backup is kept and how to find the passphrase, if there is one. For larger sums, a multisig arrangement that requires approval from more than one person makes this plan more robust.
Frequently asked questions
Is a 12-word or 24-word seed phrase more secure?
Both are far too strong to brute-force. In practice, the real risk comes from how the words are stored, not how many there are.
Is a seed phrase the same as a private key?
No. A private key controls a single address; the seed phrase is the master backup from which all of your private keys are derived. Whoever has the seed phrase controls every address it generates.