Ethereum Address Validator

Pasting an Ethereum address into a smart-contract call, a wallet import, or a transfer form with a typo sends funds to the wrong address permanently. The EIP-55 checksum exists specifically to catch that class of mistake: it encodes a Keccak-256 hash of the address into the capitalisation of the hex digits, so any software that checks the mixed case knows within milliseconds whether the address was transcribed correctly. Ethereum Address Validator runs that check in your browser, with no wallet connection and no network call.

Paste any address or click a preset chip to load a well-known one. The tool immediately reports whether the checksum is valid, wrong, or absent, identifies a handful of notable contracts by name, and provides all three canonical forms (EIP-55 checksummed, lowercase, uppercase) with one-click copy on each.

Worked Example: Spotting a Bad Checksum

Click the Bad checksum preset chip. It loads the USDC contract address in all-lowercase: 0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48. The status banner reads “All lowercase — no EIP-55 checksum applied. Valid address; use the checksummed form to prevent typo errors." The checksummed form shown below it is 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48 — only the capitalisation differs, but that pattern is a verifiable fingerprint of the address. Now change a single character in the input field: the status immediately switches to red and reports the address as invalid.

What Each Status Means

• Valid EIP-55 checksum: the mixed-case pattern matches the Keccak-256 hash of the lowercase address. This is the highest-confidence form — copy the checksummed version for any use that accepts it.
• Wrong checksum: the address contains both upper and lower case letters but they do not match the expected checksum. This can indicate a transcription error or a tool that applied a non-standard capitalisation. The address may still be a real address — the checksum only tells you that the capitalisation is not trustworthy.
• All lowercase / all uppercase: the address is technically valid hex but carries no checksum information. Both are safe to use; the checksummed form adds no extra security, only typo-detection.
• Not a valid address: the input is not exactly 40 hex characters after stripping the 0x prefix, or it contains non-hex characters. The message reads “must be exactly 40 hex characters (0–9 and a–f), with or without a 0x prefix."

Edge Cases Worth Knowing

• Checksum validity is network-agnostic. EIP-55 is applied to the 20-byte hex representation of the address, which is the same on Ethereum mainnet, all EVM testnets, and EVM-compatible chains (Polygon, Arbitrum, Optimism, BSC). A valid EIP-55 checksum on one network is valid on all of them.
• ENS names and ICAP addresses are not supported. This tool validates raw 20-byte hex addresses only. ENS names like vitalik.eth and ICAP-format addresses starting with XE are different formats and will fail the format check.
• The zero address (all zeros) passes validation. It is a valid 40-character hex string with a known EIP-55 checksum of all lowercase (since Keccak-256 of 40 zeros has no nibble ≥ 8 for any of the relevant positions). It is identified as “Zero address / burn address” in the known-contract label.