This tool generates a BIP-39 compliant Bitcoin seed phrase (12, 18, or 24 words) right in your browser, using top-tier cryptographic standards for maximum security.
Local Randomness: Powered by crypto.getRandomValues(), a cryptographically secure random number generator built into your browser. It pulls entropy (128, 192, or 256 bits) from your device’s OS—hardware noise, not weak guesses like Math.random(). No external servers involved.
Embedded Wordlist: Uses the official 2048-word BIP-39 English list, stored directly in this file. No network fetches mean no risk of tampering or interception.
Checksum Protection: Adds a checksum (4, 6, or 8 bits, based on word count) from a SHA-256 hash of the entropy. This makes your phrase valid and verifiable by standard wallets.
Offline Security: Save this as an HTML file (right-click, "Save As"), then open it locally with your browser disconnected from the internet. Running it offline eliminates browser risks like extensions or network leaks, relying solely on your system’s cryptography. For extra safety, use a clean browser with no extensions.
Wallet Compatibility: Your generated seed phrase works with most BIP-39 compliant wallets. Hardware wallets like Ledger (24 words default), Trezor (12 or 24 words), and KeepKey (12 words) fully support it. Software wallets like Electrum (imports BIP-39 despite its own standard), Blockstream Green, Coinomi, and Trust Wallet also recognize these phrases. Even Lightning wallets like Eclair use BIP-39, though some (e.g., LND’s AEZEED) use the same wordlist with a different scheme. Non-BIP-39 wallets (e.g., older Electrum seeds) need conversion via tools like Ian Coleman’s converter.
Safety Notes: The seed clears automatically after 5 minutes, or use the "Clear" button. Verify your phrase manually with a tool like Ian Coleman’s to ensure correctness. For real funds, consider a hardware wallet or a dedicated offline tool over a browser-based solution.