Unity GameObject extension to calculate its bounds.

GetBounds.cs

public static Bounds GetBounds(this GameObject gameObject)
{
    var bounds = new Bounds(gameObject.transform.position, Vector3.zero);
    var renderers = gameObject.GetComponentsInChildren<Renderer>();

    foreach (var renderer in renderers)
    {
        bounds.Encapsulate(renderer.bounds);
    }

    return bounds;
}