$re = '/^\s*(?:\(\d{3}\)\s*|\d{3})-?\d{3}-?\d{4}\s*$/m';
$str = '(404) 666-1111
(404) 6661111
404-666-1111
404-6661111
404666-1111
4046661111
(404) 666-1111
(404)666-1111
404-666-1111
404-6661111
4046661111
+1 (404) 666-1111
( 404)666-1111
404.666.1111
404 666-1111
404 666 1111
(404-666-1111';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php