# headerSize

> Total size, in bytes, of the header sections across all serialized files in the build output.

## Definition

* **Type:** Property
* **Namespace:** [UnityEditor.Build.Reporting](/engine/6000.7/script-reference/unityeditor/build/reporting.md)
* **Assembly:** UnityEditor.CoreModule

```csharp
public ulong headerSize { get; }
```

### Remarks

Each serialized file has a header and metadata section, that contains the object table, TypeTrees and external file dependency information.  The rest of each file is dedicated to storing the serialized state of the Unity Objects assigned to that file. This size is calculated before any compression is applied. Header size is included in the [\_serializedFileSize](/engine/6000.7/script-reference/unityeditor/build/reporting/contentsummary/serializedfilesize.md) total.