CRYPTO GUIDANCE INC.

Kansas City, MO

What Is BIP-39?

Published 2026-08-15. Last updated 2026-08-15. Written by John Alewine, Crypto Guidance Inc.

BIP-39 is the Bitcoin Improvement Proposal that turned a pile of random bits into the 12 or 24 word seed phrase you were told to write on paper. Most modern wallets, Bitcoin and otherwise, speak it. That is why a phrase from one honest wallet can often be recovered in another. It is a word list and a checksum, not a vault and not a company.

Who This Is For

Anyone who has a phrase in a drawer and wants to know what those words actually are. It is not a reason to type the phrase into a website "to check it." Compatibility is for recovery on a device you trust, usually after you unplugged it from the internet.

How It Actually Works

The wallet makes entropy, encodes it as words from a published list (English is the common one), and adds a checksum word so a typo is likely to fail loudly.
Those words become a seed. From the seed, wallets derive many keys along a path (BIP-32 / BIP-44 and friends). The phrase is the root. One phrase, many addresses, many coins if the wallet supports them.
A passphrase ("25th word") is optional extra secret. It makes a different wallet from the same 24 words. Forget it and the visible phrase opens an empty account. I only add one for people who will remember it as well as they remember the paper.

Risks I See in Sessions

Photographing the card. Cloud backups of seed photos are how tidy people get cleaned out.
Assuming every wallet with 12 words is the same derivation path. Recovering a Solana phrase into an Ethereum-only app can look like a zero balance. The coins are not gone. The app is looking at the wrong tree.
Steel backups that copy the words wrong. Proofread twice. See the Security page.

When It Matters

The day you create the wallet, and the day you test a recovery on a spare device before you put real money on it. I make people do that test. It is boring. It is the whole product.