If you want to get the level of the current page in WordPress you can use this
// gets the depth of the current page
global $wp_query;
$object = $wp_query->get_queried_object();
$parent_id = $object->post_parent;
$depth = 0;
while ($parent_id > 0) {
$page = get_page($parent_id);
$parent_id = $page->post_parent;
$depth++;
}
echo $depth;
This function will echo the depth of the current page. If the depth returned is zero then you’re on a parent page.
Or you could use something like this:
$ancestors=get_post_ancestors($post->ID);
$root=count($ancestors)-1;