What is a recovery phrase? The 12 or 24 words explained

What the recovery phrase of a crypto wallet is, why it is the wallet itself, how the words are made under the BIP39 standard, and what BitBox's microSD backup is.

Key points

The recovery phrase is a list of 12 to 24 words. All your keys are made from it, so the words are your wallet, not the device.
If the device breaks or gets lost, the words restore your coins on a new one. Whoever else gets the words can take your coins.
Never type the words into a computer, phone, website, or app. Write them down and keep them offline.

The words are the wallet

A hardware wallet does not store your coins. The coins are on the blockchain. The device holds the keys that let you move them, and all these keys are made from one secret: the recovery phrase, also called seed phrase.

That has two consequences:

The device is replaceable. If it breaks, gets lost, or is stolen, you can type the words into a new device and get all your coins back.
The words are irreplaceable. If you lose them and the device, the coins are gone. If someone else gets them, they can take your coins from any device, anywhere.

How the words are made

Most wallets follow the standard BIP39. The device creates a random number and adds a checksum to it, so that a mistyped word is noticed. The result is split into groups, and each group picks one word from a fixed list of 2,048 English words. The standard allows 12, 15, 18, 21, or 24 words.

BitBox, for example, uses 24 words by default and offers 12 as an advanced option. BIP39 also allows an optional passphrase on top of the words. The guide Passphrase and multisig explains when that helps.

BitBox’s microSD backup

The BitBox02 offers a second kind of backup: a file it writes to a microSD card. BitBox states that this file is not encrypted and that the device password does not protect it. Treat the card like the written words. BitBox offers an offline tool that turns the file back into the 24 words, for emergencies only.

Rules for the words

Write them down by hand on the card that comes with the device, or punch them into steel.
Never type them into a computer, phone, website, password manager, cloud service, support chat, or AI tool. BitBox lists all of these.
Never photograph, scan, or copy them.
Store them apart from the device, so that one burglary does not get both.
Never give them to anyone. No real support team asks for them.

Next step

The guide Store your recovery phrase safely shows where and how to keep the words.

The figures in this guide come from the archive and change with every data update. As of November 13, 2026.