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Ethereum Address Checksum Tool (EIP-55)

Checksummed

Convert any Ethereum address to its official EIP-55 checksummed form and verify whether a given mixed case address is valid. EIP-55 encodes a checksum in the capitalization of the hex letters of an address, using the Keccak-256 hash of the lowercase address to decide which letters are uppercase. This catches most typos, because a single wrong character almost always breaks the capitalization pattern, which is why wallets warn you when an address fails its checksum. Paste a forty character hex address with or without the 0x prefix, and the tool returns the correctly checksummed version and tells you if your input already matched. The Keccak hashing runs in pure JavaScript in your browser, so your addresses are never sent anywhere. This is handy before sending funds, whitelisting an address, or hardcoding one in a contract.

How to use Ethereum Address Checksum Tool

  1. Paste a 0x Ethereum address.
  2. Read the checksummed EIP-55 form the tool produces.
  3. Use the validity result to confirm the address casing is correct.

Frequently asked questions

What is an EIP-55 checksum address?

It is a mixed case version of a 0x address where letter casing encodes a checksum, letting wallets catch typos before sending funds.

How does the checksum validation work?

The tool hashes the lowercase address and uses the hash to decide which letters are uppercase, then compares that to your input.

Can it fix a lowercase address?

Yes. Paste an all lowercase or uppercase address and the tool returns the correctly checksummed mixed case form.

What is Ethereum Address Checksum Tool?

Convert any Ethereum address to its official EIP-55 checksummed form and verify whether a given mixed case address is valid. EIP-55 encodes a checksum in the capitalization of the hex letters of an address, using the Keccak-256 hash of the lowercase address to decide which letters are uppercase.

Is Ethereum Address Checksum Tool free to use?

Yes. Ethereum Address Checksum Tool is completely free, with no sign-up and no usage limits.

Does Ethereum Address Checksum Tool work in a web browser?

Yes. Ethereum Address Checksum Tool runs in any modern web browser. There is nothing to download or install.

Is my data private with Ethereum Address Checksum Tool?

Yes. Ethereum Address Checksum Tool runs entirely on your device in your browser, so nothing you enter is uploaded to a server.