Bitcoin Burger utility

Mnemonic Tools

Generate and validate BIP39 seed phrases

What is BIP39?

BIP39 is a Bitcoin Improvement Proposal that defines how to generate mnemonic phrases for deterministic wallets.

These phrases consist of 12-24 words from a standardized list of 2048 words, making it easier to backup and restore wallets.

The mnemonic phrase can generate all private keys for a hierarchical deterministic (HD) wallet.

Security Best Practices

  • • Generate mnemonics offline on an air-gapped computer
  • • Write down the phrase on paper, never store digitally
  • • Verify the phrase by restoring a test wallet
  • • Store multiple copies in secure, separate locations
  • • Never share your mnemonic phrase with anyone
  • • Consider using a passphrase for additional security

Mnemonic Length & Security

12
words
128 bits
Standard
15
words
160 bits
Enhanced
18
words
192 bits
High
21
words
224 bits
Very High
24
words
256 bits
Maximum

How BIP39 seed phrases work

A BIP39 mnemonic is a human-readable encoding of random entropy plus a checksum. Software converts those words into a binary seed, then into hierarchical deterministic (HD) keys following BIP32/BIP44-style derivation paths used by modern wallets.

Because the word list is fixed and checksummed, wallets can detect many typos. Validation on this page checks BIP39 structure—it does not prove a phrase was generated securely or that you control funds.

Threat model: Generation here runs in your browser and is not sent to Bitcoin Burger servers. Malware, browser extensions, compromised devices, or shoulder-surfing can still expose a phrase. See our security & privacy page for what is client-side versus what hits public APIs on other tools.

Frequently asked questions

What is a BIP39 mnemonic?
BIP39 defines how a random number (entropy) maps to a list of 12–24 words from a fixed 2048-word list, plus a checksum. Wallets derive HD keys from that phrase so you can restore accounts from a backup.
Is generating a seed phrase in a browser safe?
This tool creates phrases client-side with cryptographically secure randomness when available, and does not upload your phrase to our servers. A networked computer can still be compromised. For significant funds, generate offline on an air-gapped device or use a hardware wallet.
12 words vs 24 words—what is the difference?
12 words encode 128 bits of entropy; 24 words encode 256 bits. Both are standard. Longer phrases increase entropy; operational security (how you store the backup) usually matters more than the extra bits for everyday users.
What is an optional passphrase?
BIP39 allows an extra passphrase (sometimes called the “25th word”) mixed into seed derivation. It creates a different wallet from the same word list. If you use one, losing it means losing access—even with the words.
Also on the menu

Related tools

Keep going—these utilities pair well with what you just used.