EthTools

ETH Unit Converter

Convert between Wei, Gwei, Finney, and Ether. Uses BigInt for full precision — no floating point errors.

1 ETH 0.1 ETH 0.01 ETH 100 Gwei (gas)

Address Checksum Validator

Validate Ethereum addresses and convert to EIP-55 checksum format. Detects invalid addresses and mixed-case errors.

EF Address Invalid

Keccak256 Hash Calculator

Compute the Keccak-256 hash of any text or hex data. This is the hash function used throughout Ethereum (addresses, storage, signatures).

Keccak256 Hash
Hash will appear here
hello empty string 0xff

Hex / Decimal / Binary Converter

Convert between hexadecimal, decimal, and binary. Supports arbitrarily large numbers via BigInt.

256 0xdeadbeef uint256 max

Event Topic Calculator

Calculate the topic0 hash for Solidity event signatures. Used for filtering logs and decoding events.

Topic0 (Keccak256 of signature)
Topic hash will appear here
Transfer Approval Swap OwnershipTransferred

Function Selector Calculator

Calculate the 4-byte function selector from a Solidity function signature. The first 4 bytes of the Keccak256 hash of the canonical signature.

Selector (4 bytes)
—
Full Keccak256
—
transfer approve balanceOf swapExactTokens…

Storage Slot Calculator

Calculate the storage slot for Solidity mappings. For mapping(keyType => valueType) at slot p, the value for key k is at keccak256(abi.encode(k, p)).

Concatenated (key . slot) — 64 bytes hex
—
Storage Slot (keccak256)
Computed slot will appear here
key=1, slot=0 address key, slot=2

Epoch Timestamp Converter

Convert between Unix epoch timestamps (seconds) and human-readable dates. Commonly used in Solidity for block.timestamp.

Human-Readable (UTC)
Date will appear here
Local Time
—
Date to Timestamp
Unix Timestamp
Timestamp will appear here
Genesis (0) ETH Launch The Merge

Support EthTools

EthTools is 100% free, open source, and runs entirely in your browser. No ads, no tracking, no backend. If you find it useful, consider sending a small donation.