Ethereum Address Checksum (EIP-55)
Validate an address and convert it to its EIP-55 checksummed form to catch typos before you send.
EIP-55 adds a checksum to an Ethereum or Monad address by capitalizing certain hex letters based on the address's own hash. This tool validates an address and returns its correct mixed-case checksummed form, so a single mistyped character is caught before funds are sent to the wrong place.
An Ethereum/Monad address is 20 bytes — 40 hex characters after the 0x prefix. Hex is case-insensitive, so the raw address can be written all-lowercase. EIP-55 uses the casing of the letters (a–f) to encode a checksum derived from the keccak256 hash of the lowercase address.
Wallets and explorers display the checksummed form and reject addresses whose mixed-case casing does not match, which catches the most common typo errors. A purely lowercase address is still valid input, but it carries no checksum protection until you convert it.
This tool tells you whether the address is valid, whether it was already correctly checksummed, and gives you the canonical checksummed and lowercase forms to copy.
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