$re = '/^(?=(?:\+|0{2})?(?:(?:[\(\-\)\.\/ \t\f]*\d){7,10})?(?:[\-\.\/ \t\f]?\d{2,3})(?:[\-\s]?[ext]{1,3}[\-\.\/ \t\f]?\d{1,4})?$)((?:\+|0{2})\d{0,3})?(?:[\-\.\/ \t\f]?)(\(0\d[ ]?\d{0,4}\)|\(\d{0,4}\)|\d{0,4})(?:[\-\.\/ \t\f]{0,2}\d){3,8}(?:[\-\s]?(?:x|ext)[\-\t\f ]?(\d{1,4}))?$/mi';
$str = '911
123456789
12345678
1234567890123
001231234567890
0012312345678901
123456789012
1234
0091234567890
+9 123-4567890-x321
+9-123-456-7890
+9 123 4 5 6-7890x1234
009-(123)-456-7890 ext4321
0091234567890x1234
+9-123-456-7890x12345
+9-123-456-7890 ext 1234
00123-(4321)-567.89 ext-4321
0027-123-456-7890
+27-123-456-7890
+9(123)4567890
(01 55) 1234 5678
(01 551) 12345678
+49 (1234) 567890
(0)123456789
+34123456789
+34 (0)123456789
+340123456789
+34 123 456 789
+34 1 23 45 67 89
001230123456789
ext1234
++34123456789
00-0-----000
01 555012345
001-555012345
+012345678
112
12(34567890
123)456789012345
1-234-567-8901
+1-234-567-8901 x1234
0011-234-567-8901 ext1234
)234( 567 8901
(234) 567 8901
+11 (234) 567-8901
+1.234.567.8901
+1/234/567/8901
12345678901
2345678901';
preg_match_all($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