Cryptography & Security

BIP39 Mnemonic Generator

Create a standards-compliant mnemonic phrase for wallet development and testing, with optional passphrase-based seed derivation.

Free & unlimitedRuns in your browserNo sign-up required

Generate Mnemonic Phrase

Validate Mnemonic Phrase

Security Warning: This tool runs entirely in your browser. However, for real cryptographic funds, never use a phrase generated on a web page. Use a dedicated hardware wallet.

BIP39 Mnemonic Generator

If you've ever set up a cryptocurrency wallet, you've seen a list of 12 or 24 seemingly random words and been told to write them down and never lose them. That word list is a BIP39 mnemonic phrase, and it's the entire security of your wallet compressed into human-readable form. BIP39 (Bitcoin Improvement Proposal 39) defines a standard way to turn a random number, the actual cryptographic seed, into a sequence of words from a fixed 2048-word list.

Why use words instead of hex?

A raw 256-bit seed looks like a meaningless string of hex characters that's brutal to write down and verify by hand. A 24-word phrase built from common English words is far easier for a human to transcribe correctly, and small typos are easier to catch because the words are validated against the known list.

Phrase length and security

More words means more entropy. A 12-word phrase encodes 128 bits of randomness, already far beyond what's brute-forceable with any current or foreseeable technology. A 24-word phrase encodes 256 bits, matching the security level of AES-256. Most wallets default to 12 words for everyday use and offer 24 as an option.

Security warning

This is a genuinely sensitive tool to use online, so a direct warning: never generate a mnemonic phrase here that you intend to use for a wallet holding real funds. Use this for learning how BIP39 derivation works, testing wallet software, or verifying your own offline-generated phrase follows correct checksum rules. For anything holding actual money, generate the phrase on an air-gapped device.

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How it works

Three steps, no setup

Choose a word count

More words mean more entropy — 24 words is the strongest option.

Generate the phrase

Words are pulled from the official BIP39 wordlist using cryptographically secure randomness.

Derive a seed (optional)

Add an extra passphrase to produce a different seed from the same mnemonic.

Common questions

Frequently asked questions

Should I use this for a real wallet?

Treat any phrase generated in a browser as a test value only. Real funds belong in a hardware wallet that generates and stores keys offline.

What is BIP39 exactly?

It is a standard for turning random entropy into a human-readable list of words, making it easier to back up and restore a cryptographic seed by hand.

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BIP39 Mnemonic Generator

Why use words instead of hex?

Phrase length and security

Security warning

Three steps, no setup

Choose a word count

Generate the phrase

Derive a seed (optional)

Frequently asked questions

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BIP39 Mnemonic Generator

Why use words instead of hex?

Phrase length and security

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