BIP39 Passphrase Generator
Generate a standards-compliant BIP39 mnemonic seed phrase, or validate an existing one's checksum - for wallet development, testing, and education.
A BIP39 phrase can control real cryptocurrency funds. Never enter a seed phrase protecting real funds into any website, including this one - use a dedicated hardware wallet for that. This tool is intended for development, testing, and educational use with test wallets only.
Validate an existing phrase
Recommended Settings
Pro Tips
- •12 words is the most common length used by wallets like MetaMask and many hardware wallets; 24 words provides extra entropy and is used by some wallets by default
- •Every phrase includes a built-in checksum, so a single wrong or mistyped word will almost always be caught by validation
- •The passphrase is hidden by default - click to reveal it only when you're ready, ideally when no one else can see your screen
- •For real funds, always write your seed phrase down on paper and store it offline - never save it in a text file, email, or password manager connected to the internet
Most Popular
Most developers generate 12-word phrases for testing wallet integrations and demo applications
When to Use This Tool
Generate test seed phrases while building or testing cryptocurrency wallet software.
Understand the BIP39 standard used by most modern cryptocurrency wallets.
Create a phrase for a test wallet with no real funds, for development purposes.
Check whether a phrase you've written down has a valid checksum before relying on it.
How It Works
Generate cryptographically random entropy (128 to 256 bits, depending on word count)
Compute a SHA-256 checksum of that entropy and append the first few checksum bits to it
Split the combined bits into 11-bit groups, each mapping to one word from the standard 2048-word BIP39 list
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Web Crypto API (SHA-256), official BIP39 English wordlist for optimal performance on modern browsers.
Open Source
Built with verified, open-source libraries. Fully transparent.
Frequently Asked Questions
Is it safe to generate a real wallet seed phrase with this tool?
We strongly recommend against it. While the generation happens entirely in your browser, any website handling something as sensitive as a real wallet seed carries risk - use a dedicated hardware wallet or offline, audited software for real funds instead.
What is a checksum used for?
The last few words of a BIP39 phrase encode a checksum of the earlier entropy, which lets wallets (and this tool's validator) detect a mistyped or incorrectly ordered word before it causes a problem.
Can I use this phrase with any wallet?
Yes, BIP39 is a widely adopted standard supported by the vast majority of cryptocurrency wallets, though the specific derivation path used to generate addresses from the phrase can still vary between wallets.
Is my data sent to a server?
No. The entire phrase is generated and validated locally in your browser.
Why is the phrase hidden by default?
To reduce the chance of it being visible on your screen to someone nearby (shoulder surfing) or accidentally captured in a screen recording or screenshot.