Ethereum Address Validator

An Ethereum address is 20 bytes written in hexadecimal: 40 characters after the 0x prefix. Unlike Bitcoin, the base format carries no built-in checksum, so a single altered character produces another perfectly valid-looking address. EIP-55 fixes this by encoding a checksum in the capitalisation of the hex digits.

The mechanism is simple. Take the lowercase address without the 0x, compute its keccak-256 hash, and walk it character by character: when the corresponding hash digit is 8 or higher, the letter is uppercased. Digits have no case, so only the letters a through f carry checksum information. This means an all-lowercase or all-uppercase address is structurally valid but unprotected, while a mixed-case address that does not match the pattern is almost always corrupted.

The tool reports those three states explicitly: valid checksum, invalid checksum and no checksum. If your address arrives in lowercase, it hands back the correctly EIP-55-formatted version to use from then on. It also flags the zero address, which is the usual destination for token burns and almost never what you want as a recipient.

Because the address space is identical across every EVM-compatible chain, the same address exists on Ethereum, Arbitrum, Base, Polygon, Optimism and BNB Chain. That is exactly what local validation cannot resolve: verifying the checksum does not tell you which network holds the funds, or whether the destination contract exists on the chain you are about to use. Sending to the wrong network is a common mistake and no checksum catches it.