View difference between Paste ID: VAy3C0qe and UpgwG5Zn

 function custom_posts_per_page( $query ) {
 	if ( ! is_admin() && $query->is_main_query() )
 		$query->set( 'posts_per_page', 5 );
 }
 add_action( 'pre_get_posts', 'custom_posts_per_page' );