BENCH

Ethereum Address Checksum (EIP-55)

Apply the EIP-55 mixed-case checksum to an Ethereum address

How it works

EIP-55 adds a checksum to Ethereum addresses by selectively capitalizing the hex digits based on the Keccak-256 hash of the lowercase address. Wallets use the resulting mixed-case form to catch typos. Paste any address (with or without the 0x prefix) to get its checksummed version.

Frequently asked

What is an EIP-55 checksum?

It encodes a checksum into the capitalization of an Ethereum address's hex characters. Each letter is uppercased when the corresponding Keccak-256 hash nibble is 8 or higher, allowing wallets to detect mistyped addresses.

Does this verify the address on-chain?

No. It computes the canonical mixed-case form locally. It does not check whether the address exists or holds a balance.

Keccak-256 or SHA-3?

Ethereum uses the original Keccak-256 (pre-standardization), which differs from NIST SHA3-256. This tool uses Keccak-256, as the EIP-55 specification requires.