What is an Ethereum Address?

An Ethereum address is a 42-character hexadecimal string that serves as a unique identifier for accounts on the Ethereum blockchain. Every address starts with "0x" followed by 40 hexadecimal characters (0-9 and a-f). These addresses can represent either externally owned accounts (controlled by private keys) or smart contracts deployed on the network.

What is EIP-55 Checksum?

EIP-55 is an Ethereum Improvement Proposal that introduced a checksum mechanism using mixed-case encoding. Unlike Bitcoin addresses that have built-in checksums, early Ethereum addresses were case-insensitive, making typos undetectable. EIP-55 solves this by capitalizing specific letters based on the address hash—if you change even one character, the checksum becomes invalid. This simple yet effective method catches most typing errors before funds are sent to wrong addresses.

How Does Checksum Validation Work?

The EIP-55 checksum works by hashing the lowercase address and using the resulting hash to determine which letters should be capitalized. If a character in the hash is 8 or higher (in hexadecimal), the corresponding letter in the address is uppercase; otherwise, it's lowercase. When validating, the same process is applied—if the capitalization matches the expected pattern, the checksum is valid.

Tool Description

This tool validates Ethereum wallet addresses and verifies their EIP-55 checksum encoding. Simply paste an address to instantly check if it's a valid Ethereum address, see its format type, and confirm whether the checksum is correct. The validator handles all common address formats including checksummed, lowercase, and uppercase variants.

Features

  • Instant validation — Verify any Ethereum address format in real-time
  • EIP-55 checksum verification — Detect if addresses have valid mixed-case checksums
  • Format detection — Identify whether addresses are checksummed, lowercase, or uppercase
  • Length validation — Confirm addresses have the correct 42-character length
  • Copy-paste friendly — Handles addresses with extra whitespace automatically

Use Cases

  • Before sending crypto — Validate recipient addresses to prevent irreversible fund loss
  • Smart contract development — Verify contract addresses during deployment and testing
  • Wallet integration — Check user-submitted addresses in dApps and exchanges
  • Security auditing — Confirm addresses in configuration files and code repositories