Back up your seed words

What the seed words are

Your wallet makes 12 or 24 words from a fixed list of 2,048 words. The list is part of a standard called BIP39.

Because it’s a shared standard, those words can rebuild your wallet in any app that supports it. Phones and devices break or get lost. With the words, you get everything back.

The same is true for anyone else who has them. Whoever holds the words can spend your Bitcoin, which is why the rest of this guide is about keeping them private.

Seed words Also called a recovery phrase or seed phrase. The same thing under different names.

Write them down by hand

Do this once, slowly.

1. Use a pen. Pencil fades and smudges.
2. Number each line, 1 to 12 or 1 to 24.
3. Write each word in order, in clear capital letters.
4. Check every word against the screen before you move on.

Each word on the list can be told apart by its first four letters. If your handwriting is messy, make sure those four are clear.

Keep them off anything online. Don’t take a photo, don’t type them into a phone or computer, and don’t save them in the cloud. A real wallet will never ask you to type them into a website.

Paper or metal

Paper is free and it works. It can burn, get wet or fade over the years, so keep it dry and out of the light.

Metal plates are stamped or engraved with your words. They survive fire and water much better than paper. They cost money, so they are optional.

If you buy one, buy it from the maker’s own shop. Then copy the words onto it from your paper, in private.

Paper is fine to start. You can move the words to metal later.

Where to keep your backup

One copy in one place can be lost in one bad day. Bitcoin.org suggests keeping copies in more than one place, on something that lasts.

• Every copy is a full key to your Bitcoin. Only keep a copy where you would keep cash.
• Don’t write “Bitcoin” on it. A plain card in a folder draws less attention.
• Think about your family. Someone you trust should know how to find it, or how to reach someone who knows.

Using a passphrase, sometimes called the 25th word? It makes a separate wallet, and it needs its own backup. Keep it in a different place from the words.

Passphrase An extra word or sentence you choose. With it, the same seed words open a different wallet.

Test the backup

A test shows the words are right while everything is calm, long before you ever need them. It takes a few minutes and doesn’t move any coins.

If your device has a backup check. Some devices have a check that compares the words you type with the ones it stores. Nothing gets saved or changed.

If it doesn’t. Type the words into an offline signer, like a SeedSigner. It shows a short code called a fingerprint. Your wallet app shows the same code in the wallet’s settings. If the two match, your words are right. The SeedSigner guide, step 14, walks through this.

If they don’t match, check each word and try again. If it still fails, make a new wallet with a new backup and move your coins to it soon. Then test the new backup.

Only type your words into the offline device itself. Never into a phone, a computer or a website.

One step for today

Check the backup you already have. It takes about 20 minutes and you don’t need to buy anything.

1. Find a private spot with no cameras around.
2. Get your written words.
3. Run your device’s backup check, or compare fingerprints as in step 5.
4. If any word is hard to read, write a clean copy and destroy the messy one.

If it matched, your backup works. Put it back where it lives.