> ## Documentation Index
> Fetch the complete documentation index at: https://hedera-0c6e0218-mintlify-bc559771.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# ContractID

> ContractID is the Hedera protobuf identifier for a smart contract instance, addressing it by shard, realm, and contract number on the network.

The ID for a smart contract instance

| Field         | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| ------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `shardNum`    | The shard number (nonnegative)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| `realmNum`    | The realm number (nonnegative)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| `contractNum` | A nonnegative number unique within its realm                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| `evm_address` | <p>The 20-byte EVM address of the contract to call. Every contract has an EVM address determined by its shard.realm.num id. This address is as follows:<br /><br />The first 4 bytes are the big-endian representation of the shard.<br /><br />The next 8 bytes are the big-endian representation of the realm.<br /><br />The final 8 bytes are the big-endian representation of the number.<br /><br />Contracts created via CREATE2 have an <strong>additional, primary address</strong> that is derived from the <a href="https://eips.ethereum.org/EIPS/eip-1014">EIP-1014</a> specification, and does not have a simple relation to a shard.realm.num id. (Please do note that CREATE2 contracts can also be referenced by the three-part EVM address described above.)</p> |

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