wp-custom-excerpt-length.php

<?php

/** 
 * Filter the except length to any specified length of words. 
 * 
 * @param string $content the content 
 * @param int $length Excerpt length. 
 * @return int (Maybe) modified excerpt length. 
 */
function catchy_labs_custom_excerpt($content, $limit) {
  $excerpt_no_shortcodes = strip_shortcodes($raw_excerpt);
  $excerpt = explode(' ', strip_tags($excerpt_no_shortcodes), $limit);
  
  if (count($excerpt)>=$limit) {
      array_pop($excerpt);
      $excerpt = implode(" ",$excerpt).' [...]';
  } else {
      $excerpt = implode(" ",$excerpt);
  }    
  
  $excerpt = preg_replace('`[[^]]*]`','',$excerpt);
  return $excerpt;
}

?>

<div class="the-excerpt">
  <p><?php echo catchy_labs_custom_excerpt( get_the_content(), 45 ); ?></p>
</div>