CryptoAPIsOffline: nothing is sent

Check an EVM address checksum

Paste one address or a list. Each is checked for 0x + 40 hex digits and, when mixed-case, for its EIP-55 checksum. Characters with the wrong case are highlighted.

A valid checksum only means the text was not mistyped. It does not tell you who controls the address, whether it holds funds or code, or whether it is safe to send to.

Profile: EVM, EIP-55. Chain-specific checksum variants (EIP-1191) are not supported in this release.

Checked 6Checksum valid 2Problems 3
AddressResult
0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAedChecksum valid

EIP-55 checksum matches.

0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed
EIP-55: 0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed
No checksum (lowercase)

Valid syntax, all lowercase: no checksum to verify. Typos cannot be detected.

0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAeD
EIP-55: 0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed
Checksum mismatch

EIP-55 checksum does NOT match (1 character with the wrong case). The address may be mistyped. Do not "fix" it by re-casing without checking the source.

0x000000000000000000000000000000000000dEaDChecksum valid

EIP-55 checksum matches.

0x000000000000000000000000d8da6bf26964af9d7eed9e03e53415d37aa96045Wrong length

Has 64 hex digits; an EVM address has exactly 40 (20 bytes).

  • Note64 hex digits is 32 bytes: this may be a transaction hash, a block hash, a topic or an ABI-padded word, not an address.
  • NoteIf this is an ABI word, the address is the last 20 bytes: 0xd8da6bf26964af9d7eed9e03e53415d37aa96045.
fB6916095ca1df60bB79Ce92cE3Ea74c37c5d359
EIP-55: 0xfB6916095ca1df60bB79Ce92cE3Ea74c37c5d359
Missing 0x

Missing the "0x" prefix. The 40 hex digits look like an address body.

Syntax and checksum only. This says nothing about ownership, balances, deployed code or safety.

Checking for a saved draft…

How EIP-55 works

Take the 40 lowercase hex digits, hash them with Keccak-256, and uppercase each letter whose matching hash nibble is 8 or higher. An all-lowercase or all-uppercase address carries no checksum, so a typo in it cannot be detected; the checker labels these separately rather than calling them valid checksums.

Common mix-ups

  • 64 hex digits is 32 bytes: a transaction hash, block hash, topic or ABI-padded word, not an address. If the first 24 digits are zeros, the last 40 may be an address.
  • The zero address 0x000…000 is used as a burn or "none" sentinel.
  • Some chains define their own checksum rules (for example EIP-1191 on RSK). This release checks EIP-55 only and says so.

Questions

My wallet shows the address in lowercase. Is it wrong?

No. Lowercase is valid syntax; it simply has no checksum. Checksummed form is safer to share because a typo is detectable.

Should I fix the case if the checksum fails?

Not blindly. A failing checksum means at least one character may be wrong. Re-copy the address from its original source instead of re-casing it.

Does a valid address mean the account exists?

Every 20-byte value is a syntactically valid address. Whether anything is there is chain state, which this offline tool does not read.