$re = '/(?:(\+)?(1)?([-(.])?([1-9]\d{2})([-).])?\s?([1-9]\d{2})([-.])?(\d{4})|([1-9]\d{2})([-.])?([1-9]\d{2})([-.])?(\d{4})|([1-9]\d{2})([-.])?(\d{4}))/m';
$str = '1-800-555-1212
+1-800-555-1212
1(800)555-1212
800-555-1212
800.555.1212
555-1212
';
preg_match_all($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