What Is a Seed Phrase? How It Works and How to Keep It Safe

What is a seed phrase? It is a list of words, usually 12 or 24, that many crypto wallets give you when you set them up. The words can restore the wallet, with every account in it, on a new device. Anyone who gets them can take the funds too.

How a seed phrase works

A crypto wallet is the app or device you use to reach your coins on the blockchain. A common standard called BIP-39 builds the phrase from a fixed list of 2,048 words and allows phrases of 12 to 24 words. You will usually see 12 or 24.

Not every wallet follows BIP-39. Trezor, for example, describes (opens in a new tab) a different format called SLIP39 that uses 20 words. Check your wallet's help pages to see which format yours uses.

The order matters, so word 1 must stay word 1. The last word includes a built-in check, so a wallet can often tell when a word is wrong.

One phrase recreates every account in the wallet. MetaMask says (opens in a new tab) its phrase gives access to all the accounts in that wallet. Your coins do not sit inside the phrase, the device or the app: they stay on the blockchain, and Trezor says the phrase holds everything needed to reach them there.

In wallets such as MetaMask and Trezor, the phrase is created when you set up the wallet, before any crypto arrives. Self-custody means you, not a company, hold the keys. Wallet makers use different names for the phrase, such as wallet backup (Trezor) and Secret Recovery Phrase (MetaMask).

Seed phrase vs private key, PIN and exchange login

These four secrets are easy to mix up. A private key is the secret that lets you spend from one account (address). Your wallet derives its private keys from the phrase.

On an exchange, the company holds the keys. Crypto.com says (opens in a new tab) you do not control the private keys in its App, while in its Onchain wallet you are the custodian. The storage guide compares custodial and non-custodial wallets.

How to record and keep your phrase

Do this when your wallet first shows the words, before you add any crypto.

1. Go somewhere private, where no one can see your screen or your paper.
2. Write the words on paper, numbered, in the order shown. Copy them exactly: the order is part of the phrase.
3. Pass the wallet's backup check. Some wallets ask you to rearrange the words or retype certain ones before setup finishes. If you cannot pass it, compare your paper with the screen word by word, and do not add funds until it matches.
4. Store the paper offline, safe from theft and damage, where only you can reach it.

Never make a digital copy: no photo, screenshot, email or note in a cloud app. Trezor says (opens in a new tab) this includes encrypted folders.

• Never share the words with anyone.
• Type them only into your own wallet's official app or device, when you set it up or restore it.
• Anyone who sees or copies the phrase can take everything in the wallet, even while you still hold the paper.

If you use a hardware wallet, see how to set up a hardware wallet. To plan who can reach your phrase if something happens to you, see how to make a crypto inheritance plan.

Scams that target your seed phrase or your losses

Wallet makers such as Trezor (opens in a new tab) and MetaMask (opens in a new tab) say they will never ask for your phrase, even in customer support. Treat a "support agent" who asks for the words as a scammer, including one who claims to represent the wallet maker. See how fake support agents reach you.

Look-alike wallet screens are the second pattern. MetaMask says the only times you enter the phrase are when you create a wallet (to confirm you recorded it) and when you restore it or reset your password, and that scammers try to imitate those two moments. Before typing a word, ask whether you are creating or restoring your own wallet; if not, stop.

Fake crypto recovery services are the third. In an August 2025 alert (opens in a new tab), the FBI warned that fictitious law firms target cryptocurrency scam victims and offer to recover their funds. Its red flags include a request for payment in cryptocurrency or prepaid gift cards, and it notes that the US government does not request payment for law enforcement services.

To report a scam, see where to report a crypto scam for your country.

If your phrase is lost or someone may have seen it

If someone may have seen it

Assume the phrase is compromised and move the funds to a new wallet right away. Read the checks below before you send anything.

MetaMask's advice (opens in a new tab) is to create a new wallet on a new browser, browser profile or mobile device and write the new phrase down in the correct order. Then send the remaining funds to the new account and stop using the old wallet. Do not restore the old phrase into the new wallet.

If you lost the written copy but the wallet still opens

Act now. Whether the app can show the words again depends on the wallet: Trezor says (opens in a new tab) a missing backup cannot be regenerated in any way, so you create a new wallet with a new backup and move your funds into it, using the checks above. Look in your wallet's help pages for whether it can show the phrase again, and do it while the wallet still opens.

If you lost both

Trezor and Crypto.com say (opens in a new tab) you cannot get access back if the phrase and the wallet are gone, and MetaMask says (opens in a new tab) its support cannot recover the phrase. A person or site that offers to recover it for a fee matches the fake recovery service scams.

Common misconceptions

• "My exchange has my seed phrase." On a custodial account the platform holds the keys and you hold a login.
• "My device is the backup." Trezor says (opens in a new tab) that without the written backup, a forgotten PIN or a broken device means losing access forever.
• "Support can reset it." MetaMask says (opens in a new tab) its support team has no way to recover your phrase for you.

Risks to understand

A paper copy can be damaged, lost or stolen. Trezor says (opens in a new tab) paper can tear, fade or be destroyed by fire, water or corrosion, and it sells a stainless-steel backup for that reason. A metal plate is an alternative to paper, and the rules above still apply: keep it offline and never copy it digitally. If it is gone and you lose the wallet too, you could lose all the crypto in it. Think about who can reach the place where you keep it, including people who have access to your home.

Before your first purchase, read how to buy crypto for the full path and how to choose a crypto exchange for where to buy.