Apply and check the EIP-55 address checksum

Generate or verify an Ethereum EIP-55 mixed-case checksum address.

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ToolEthereum Address Tools

Input

Output

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How it works

The 40 hexadecimal characters are lowercased and treated as ASCII text for Keccak-256. A letter is uppercased when its matching hash nibble is at least 8; digits stay unchanged and mixed-case input is compared with the computed pattern.

Lowercase and uppercase forms are shown because only mixed case carries checksum bits.
The address must contain exactly 20 bytes.

Worked example

Checksum a lowercase address

The official EIP-55 worked example

Input

											0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed

Output

												Checksum address: 0x5aAeb6053F3E94C9b9A09f33669435E7Ef1BeAed
Lowercase address: 0x5aaeb6053f3e94c9b9a09f33669435e7ef1beaed
Uppercase address: 0x5AAEB6053F3E94C9B9A09F33669435E7EF1BEAED
Is eip55 valid: yes
Reason: All one case, so there is no checksum claim to check.

When to use this

Wallets checksum recipients, explorers normalize pasted addresses, and frontends validate transaction destinations.

Edge cases

Hashing raw address bytes instead of lowercase ASCII characters gives the wrong capitalization.
All-lowercase input is accepted but offers no case-based typo detection.
One changed letter can fail the checksum while still leaving 40 hexadecimal characters.

References

EIP-55