How can I get GUILayout height?

After starting the GUI area using the GUILayout.BeginArea function and closing the GUI area using the GUILayout.EndArea function, I want to know the size between the two.

        // position = (0.0, 0.0, 100, 100)
        GUILayout.BeginArea(position);
        GUILayout.Space(5.0f);

        if (GameEditorUtility.DrawHeader("File"))
        {
            DrawFileList();
            GameEditorUtility.Button("Load", LoadFile);
            GameEditorUtility.Button("New", NewFile);
        }
        GUILayout.EndArea();

After using the GUILayout.EndArea function, the position value does not change.

You could use GUILayoutUtility.GetLastRect right after EndArea to get the rectangle used by that area.