What is the ENS namehash?

Namehash is the recursive hashing algorithm from EIP-137 that turns a human-readable name like alice.eth into a fixed 32-byte node identifier. ENS smart contracts use this node, not the string, to look up resolvers and records.

How is namehash computed?

Start with 32 zero bytes for the empty name. For each label from right to left, set node = keccak256(node + keccak256(label)). The keccak256 of a label is its labelhash.

What is the difference between labelhash and namehash?

Labelhash is keccak256 of a single label (the part between dots). Namehash is the recursive combination of all labelhashes down the hierarchy. A registrar tokenId is usually the labelhash of the second-level label.

Does ENS use SHA-256 or keccak-256?

Keccak-256, the original Keccak submission, not the later NIST SHA3-256 standard. They differ in one padding byte and produce different outputs, so namehash must use keccak-256.

Is my name sent to a server?

No. The keccak-256 hashing runs entirely in your browser with a local implementation. No network request is made, so your names stay private.

ENS Namehash Calculator

The ENS Namehash Calculator computes the 32-byte node identifier that Ethereum Name Service contracts use to resolve a name. It implements the EIP-137 algorithm, including the recursive keccak-256 hashing, entirely in your browser.

How it works

ENS contracts cannot store arbitrary strings cheaply, so every name is reduced to a fixed 32-byte node via the namehash algorithm. The recursive definition from EIP-137 is:

namehash([]) = 0x0000...0000   (32 zero bytes)
namehash([label, ...rest]) =
    keccak256( namehash(rest) || keccak256(label) )

In practice you process labels from right to left. Starting from 32 zero bytes, for each label you compute its labelhash = keccak256(label), concatenate it after the running node, and hash again with keccak-256.

Labelhash vs namehash

The labelhash is the keccak-256 of a single label between dots — for example keccak256("vitalik"). The namehash combines every labelhash down the tree. A .eth second-level registration’s NFT token ID is the labelhash of its second-level label, while resolvers are keyed by the full namehash.

Example and notes

For eth, namehash is keccak256(0x00…00 || keccak256("eth")), and vitalik.eth then becomes keccak256(namehash("eth") || keccak256("vitalik")). This tool uses keccak-256, not NIST SHA3-256 — they differ by a single padding byte and are not interchangeable. For full ENS compliance, names should also be UTS-46 normalised; this tool lowercases input but does not perform full normalisation.