Ethereum Address Validator
Check an Ethereum address format and verify its EIP-55 mixed-case checksum.
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How to use
- Paste the Ethereum address, including the 0x prefix.
- Click Validate Address.
- If it is all lowercase, note that the format passes but the checksum is absent.
- Use the checksummed form shown when a checksummed address is needed.
About this tool
An Ethereum address is 0x followed by 40 hexadecimal characters, and the EIP-55 standard adds a checksum by capitalising certain letters according to a Keccak-256 hash of the lowercase address. This validator first checks the format, then recomputes that mixed-case form with a self-contained Keccak-256 implementation and compares it letter by letter. An all-lowercase address passes the format check but is reported as not checksummed, because its capitalisation carries no checksum.
Frequently asked questions
Why does capitalisation matter in an Ethereum address?
EIP-55 turns capitalisation into a checksum: each letter is uppercased only when the matching hash nibble is eight or higher.
Is an all-lowercase address unusable?
No. Wallets accept it, but it carries no checksum protection, so a typo in it would not be caught by this check.