Global Ethereum address validator
How the Ethereum address format works
- Format
- 0x + 40 hex characters (EIP-55 checksum casing)
- Example
- 0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed
Things to watch for
- Case-sensitive — mixed-case letters encode an EIP-55 checksum
- All-lowercase or all-uppercase addresses are accepted on format alone (no checksum to verify)
- Validates the address format/checksum only — does not check balance or ownership
^0x[0-9a-fA-F]{40}$An Ethereum address is a 40-character hexadecimal string prefixed with ‘0x’ — for example 0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed — used to receive ETH, tokens, and interact with smart contracts. Anyone copying an address from a wallet, block explorer, or invoice benefits from catching a single mistyped character before a transaction is sent, since Ethereum transfers, like Bitcoin’s, can’t be reversed once confirmed.
Unlike Bitcoin addresses, Ethereum’s checksum isn’t extra characters — it’s encoded in the capitalization of the letters themselves, under a standard called EIP-55. A hash of the lowercase address determines which of its a-f letters get uppercased, so the casing itself is the check, not decoration. Addresses written in all-lowercase or all-uppercase skip this mechanism entirely and carry no checksum protection, even though they’re still technically valid.
How this validator works
This tool checks the ‘0x’ prefix and 40-hex-character length, then — if the address uses mixed case — verifies the EIP-55 checksum by re-deriving the expected casing from the address’s hash, entirely in your browser. Nothing is sent to a server, and there’s no signup.
What a pass doesn’t tell you
A pass on a mixed-case address confirms the checksum is internally consistent — real protection against a mistyped character. A pass on an all-lowercase or all-uppercase address only confirms the format (prefix and length); there’s no checksum to fail, so a mistyped character could pass just as easily as a correct one. Either way, this tool never queries the blockchain, so balance, transaction history, and contract behavior are outside what it can tell you.
Scope: this page and tool cover Ethereum address format and EIP-55 checksum validation only — not balance lookup, transaction history, or smart contract verification.
Content last reviewed 2026-07-07.
Ethereum address FAQ
What is EIP-55 checksum casing?
EIP-55 is the standard that encodes a checksum into an Ethereum address's letter casing — each hex letter (a-f) is uppercased or lowercased based on a hash of the address, so mixed-case letters aren't stylistic, they're a built-in typo check.
Is an all-lowercase Ethereum address invalid?
No — an all-lowercase (or all-uppercase) address is still a valid 40-character hex address; it simply carries no EIP-55 checksum, so this tool can confirm its format but not detect a single mistyped character the way it can for a mixed-case checksummed address.
Does this tool check my ETH balance or transaction history?
No. Validation runs entirely in your browser and never queries the blockchain, so it can't tell you a balance, transaction history, or whether an address has ever been used.