How to store your crypto seed phrase safely (and the mistakes that cost people everything)

When you set up a self-custody crypto wallet, it shows you a list of words, usually 12 or 24, and asks you to write them down. Many people treat this as a formality. It isn’t. Those words are the master key to everything in the wallet, today and in the future.

The Ethereum documentation is blunt about it: the seed phrase is often the only way you’ll be able to recover your wallet, so you should write it down and keep it safe. This guide explains how to do that, and the mistakes to avoid.

What the seed phrase is

The seed phrase (also called a recovery phrase or mnemonic) is a human-readable version of the secret from which your wallet’s private keys are generated. That’s why it can rebuild your whole wallet on a new device: every address and every key comes from it.

Two consequences follow:

1. If you lose it and your device breaks or is lost, your crypto is gone. There’s no “forgot password” for a self-custody wallet.
2. If someone else gets it, they can restore your wallet on their own device and empty it, from anywhere in the world, without needing your phone, hardware wallet or PIN.

How to store it safely

Write it down, offline

• Write the words by hand, in order, with the word numbers, on the card provided or on good paper.
• Double-check every word against the screen. Many wallets ask you to confirm some words before finishing setup; don’t skip it.
• Consider a metal backup (stamped or engraved plates), which resists fire and water better than paper.

Never store it digitally

Avoid all of these, however convenient:

• Photos or screenshots (they sync to cloud storage).
• Notes apps, email drafts, text files, password managers you don’t fully control.
• Cloud drives, messaging apps sent “to yourself”.
• Typing it into any website, form or chat.

Digital copies can be found by malware, exposed in an account breach or synced to devices you’ve forgotten about.

Keep backups in separate places

A single copy can be lost in a fire, flood or move. Keep at least two copies in different secure locations, for example a home safe and a safe deposit box, or with a trusted family member in a sealed envelope. More copies mean more resilience, but also more places where someone could find one, so balance the two.

The mistakes that cost people everything

1. Giving it to “support”

Scammers pose as wallet or exchange support, often through social media replies, fake help desks or messaging apps, and say they need your recovery phrase to “fix”, “verify” or “sync” your wallet. No genuine company will ever ask for it. If anyone asks, it’s a scam, every time.

2. Typing it into a fake website

Phishing sites copy real wallet pages and ask you to “re-enter your recovery phrase” to claim an airdrop, fix an error or upgrade. Real wallets never need your phrase except when you’re restoring a wallet yourself, on your own device.

3. Recovery scams after a loss

People who’ve already lost money are targeted again by fake recovery services. The FBI’s 2025 internet crime report recorded 10,516 complaints about recovery scams with $1.4 billion in losses (which can include losses from the original scam). Some ask for your seed phrase to “trace” or “return” funds. See our guide to crypto scams and where to report them.

4. Pre-filled recovery cards

A hardware wallet should generate a new phrase when you set it up. If a device arrives with words already written on a card, or instructions to use a phrase supplied in the box, don’t use it: the seller knows the phrase.

5. Telling people you own crypto

The more people know you hold crypto, especially a lot of it, the more likely you are to be targeted, online and offline. Keep it to yourself and the people who need to know.

Optional extra protection: a passphrase

Many wallets support an optional passphrase (sometimes called a “25th word”). It’s added to your seed phrase to create a different wallet. Someone who finds only your seed phrase can’t reach the funds protected by the passphrase.

The trade-off is serious: if you forget the passphrase, those funds are unrecoverable, even with the seed phrase. Only use one if you have a reliable way to store it separately.

Planning for your family

If something happens to you, can anyone access your crypto? Without the seed phrase, they can’t, and nobody can help them. Consider:

• A letter of instructions, kept with your will or with a lawyer, explaining what you hold and where the backups are, without writing the phrase in the letter itself.
• Making sure at least one trusted person knows how to find the backup.
• Keeping records of what you own. These also help with tax: the CRA, for example, expects records such as wallet addresses and balances to be kept for at least six years.

Quick checklist

• Written by hand, checked word by word, numbered.
• No photos, cloud, email or typed copies.
• At least two copies in separate secure places; consider metal.
• Never shared, never typed into a website, never given to “support”.
• A plan for someone you trust to access it if you can’t.

For how seed phrases fit into the bigger picture of wallets, see hot vs cold wallets.