Hex Converter
Hex Converter converts hex to UTF-8 text and decimal big integers, plus Keccak256 and function selectors. For input data and logs; local browser only.
Calculations and checks on this page run in your browser. Private keys and seed phrases are never uploaded to the server.
About this tool
Hex Converter helps inspect hex-encoded calldata, event logs and RPC return values—a basic step in transaction review and contract debugging.
It supports hex ↔ UTF-8 text, hex ↔ decimal big integers, plus Keccak256 and function selectors (first 4 bytes of the signature hash).
For example, transfer(address,uint256) has selector 0xa9059cbb, which you can match to the first 4 bytes of Input Data.
How to use
- Choose the conversion or hash function you need.
- Enter data in the input area; output updates live.
- For selectors, use the canonical ABI signature with no spaces or parameter names, such as transfer(address,uint256).
FAQ
What does the 0x prefix on hex mean?
It marks a hexadecimal literal so it is not confused with decimal. This tool accepts input with or without 0x.
Does hex-to-decimal lose precision?
No. Internals use BigInt and cover the full uint256 integer range.
Is Keccak256 the same as SHA3-256?
No. Ethereum uses pre-standard Keccak padding; final SHA3-256 differs. In Ethereum docs, “sha3” usually means Keccak256.
How do I use a function selector to parse a transaction?
The first 4 bytes of Input Data are the selector. Match them to known signature hashes to infer the called method; proxies or collisions need a verified ABI.