Ethereum Checksum Validator
Validate the EIP-55 mixed-case checksum of one or more Ethereum / EVM addresses and show the canonical checksummed form. Works for any EVM chain (Ethereum, Polygon, BSC, Arbitrum, Optimism, Base).
Input
Validates the EIP-55 mixed-case checksum. Works for any EVM chain (Ethereum, Polygon, BSC, Arbitrum, Optimism, Base, etc.).
Output
| Input | Status | Checksummed (EIP-55) | Notes |
|---|---|---|---|
| No data yet | |||
Guides
The Ethereum Checksum Validator checks whether one or more Ethereum / EVM addresses carry a correct EIP-55 mixed-case checksum, and shows the canonical checksummed form for each. Paste a single address or a whole list — one per line — and every entry is classified in a results table you can copy or download as CSV.
An Ethereum address is 20 bytes, written as 40 hexadecimal characters with an optional 0x prefix. Because hex is case-insensitive, the same address can be written all-lowercase, all-uppercase, or in a specific mix of cases. EIP-55 uses that spare capacity as a lightweight checksum: it hashes the lowercase address with Keccak-256 and uppercases each letter whose corresponding hash nibble is 8 or greater. A wallet or block explorer that produced a mixed-case address will always produce that exact pattern, so a single mistyped or transposed character almost always breaks the case pattern and is caught before you send funds.
How to use it
- Paste one address per line into the input box. The
0xprefix is optional. - Read the results table. Each row shows your input, a Status, the correct Checksummed (EIP-55) form, and a short note.
The tool works for every EVM-compatible chain — Ethereum, Polygon, BNB Smart Chain, Arbitrum, Optimism, Base, Avalanche C-Chain and others — because they all share the same 20-byte address format and EIP-55 rules.
What the statuses mean
- Valid checksum — a mixed-case address whose casing matches EIP-55 exactly. Safe to trust as correctly transcribed.
- Invalid checksum — a mixed-case address whose casing does not match. Likely a typo; compare it against the suggested checksummed form.
- Unchecksummed — an all-lowercase, all-uppercase, or letter-free address. Valid in format but carries no checksum information, so no typo protection is possible. Use the shown checksummed form going forward.
- Invalid format — not 40 hex characters. Not a usable EVM address.
FAQ
Does an all-lowercase address still work?
Yes. All-lowercase and all-uppercase addresses are accepted by every node and wallet; they simply skip the checksum safety net. The tool marks them Unchecksummed and gives you the proper mixed-case version to adopt.
Why Keccak-256 and not SHA3-256?
Ethereum uses the original Keccak-256 padding, which was finalized differently from the later FIPS-202 SHA3-256 standard. The two produce different digests for the same input, so only Keccak-256 yields correct EIP-55 checksums. This tool uses an audited Keccak-256 implementation.
Can I check many addresses at once?
Yes — paste as many as you like, one per line. Each is validated independently, and you can download the whole table as a CSV.
Does it verify that an address exists or holds funds?
No. This is a purely offline format-and-checksum check. It does not query any blockchain, so it says nothing about balances, contract code, or transaction history.
Privacy
Validation runs entirely in your browser. The addresses you paste are never uploaded, logged, or sent to any server — the Keccak-256 hashing and case comparison all happen locally on your device.