Web3 Lab · T.05
Seed Phrase Validator
Check BIP39 words and checksum — without deriving any keys. Format only, no derivation.
This validator needs JavaScript (runs locally in your browser).
Examples:
Note: Only wordlist membership and the BIP39 checksum are checked. No private key, address, or seed is derived.
What is checked here
A BIP39 seed phrase consists of a fixed number of English words (12, 15, 18, 21 or 24). The last bits of the final word contain a checksum computed from the SHA-256 hash of the entropy.
This validator checks two things: whether every entered word is in the official English BIP39 wordlist, and whether the checksum is correct. It does not derive a seed or any keys.
Frequently asked questions
Does my seed phrase leave the browser?
No. The check runs entirely locally via JavaScript. No data is sent to a server and no keys are derived.
What does "checksum valid" mean?
The phrase is a formally valid BIP39 construct. It does not mean it belongs to any particular wallet — only that it is mathematically consistent.
Can I enter my real seed phrase here?
No. The tool is for educational purposes. Real seed phrases should never be entered into any website, even trusted ones.
Why are no keys derived?
By design: the validator stops before PBKDF2 derivation. That way nothing can accidentally be exposed, even if someone uses the page online.
Seed understood — now generate a wallet?
The Wallet Generator shows how a seed phrase becomes addresses. Use offline and only with test seeds.