$re = '/^(1\s?)?(\(\d{3}\)|\d{3})[\s\-]?\d{3}[\s\-]?\d{4}$/m';
$str = '555-555-5555
1 555-555-5555
1 (555) 555-5555
5555555555
555-555-5555
(555)555-5555
1(555)555-5555
555-5555
5555555
1 555)555-5555
1 555 555 5555
1 456 789 4444
123**&!!asdf#
55555555
(6054756961)
2 (757) 622-7382
0 (757) 622-7382
-1 (757) 622-7382
2 757 622-7382
10 (757) 622-7382
27576227382
(275)76227382
2(757)6227382
2(757)622-7382
555)-555-5555
(555-555-5555
(555)5(55?)-5555';
preg_match_all($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