EIP-55 Address Checksum
Validate and generate EIP-55 checksummed Ethereum addresses.
EIP-55 Address Checksum Validator
Validate an Ethereum address and convert it to its EIP-55 checksummed format. The checksum uses Keccak-256 to determine which letters should be capitalized, catching typos before funds are lost.
0x742d35Cc6634C0532925a3b844Bc454e4438f44eEIP-55 introduces a checksum into Ethereum addresses by capitalizing certain letters based on the Keccak-256 hash of the lowercase address.
If the hash digit at position i is ≥ 8, the corresponding address character is capitalized.
What is an EIP-55 checksum?
Ethereum addresses are hexadecimal, which makes them easy to mistype and hard to verify by eye. EIP-55 solves this by encoding a checksum into the capitalization of the address: each letter is upper- or lowercased according to the Keccak-256 hash of the lowercase address. A single mistyped character almost always produces an invalid checksum.
Wallets and exchanges use this checksum to catch typos before funds are sent. An all-lowercase address contains no checksum at all — it is syntactically valid but offers no typo protection.
Features
- Validate the mixed-case checksum of any Ethereum address
- Convert a lowercase address to its checksummed form
- Detect addresses with no checksum or a broken one
- Works for EOAs and contract addresses alike
- 100% client-side — addresses are never transmitted
When to use it
Use it before sending funds to an address copied from an untrusted source, when a wallet rejects an address as invalid, when publishing an address in documentation (always use the checksummed form), or when verifying that two differently-cased strings refer to the same account.