Regular Expression for phone number including country code maximum 18 character

Question

I am want a Regular Expression that mark as correct number for below examples:

    +256897845    
    +1 232321
    +29 2343 2432 43
    +555 2356897845
    +1245 2356878
    +918989784578

Must include + Symbol on start
Optional Support up to 3 space Like: +29 2343 2432 43
Minimum 8 Char including + symbol
Max Char 18 digit (3 Space + 4 digit max country code + Plus (+) Symbol + 10 digit max number)

i have tried my self as below but not working:

^\+[0-9]?()[0-9](\s|\S)(\d[0-9]{18})$

Min 8 and max 18 requirements apply to the overall string length? Should spaces be counted? — Wiktor Stribiżew, Oct 14 '18 at 07:36
Or, the option with no whitespaces counted towards the 8-18 char limit: `^\+(?=(?:\s?\d){7,17}$)\d+(?:\s?\d+){0,3}$` — Wiktor Stribiżew, Oct 14 '18 at 07:40
@SilentCoder See [What is a non-capturing group? What does (?:) do?](https://stackoverflow.com/questions/3512471/what-is-a-non-capturing-group-what-does-do) — Wiktor Stribiżew, Oct 14 '18 at 07:57

score 2 · Accepted Answer · answered Oct 14 '18 at 07:46

You may use

/^\+(?=(?:\s?\d){7,17}$)\d+(?:\s?\d+){0,3}$/

See the regex demo

Details

^ - start of string
\+ - a plus symbol
(?=(?:\s?\d){7,17}$) - up to the end of the string, there must appear 7 to 17 occurrences of an optional whitespace and a digit
\d+ - 1+ digits
(?:\s?\d+){0,3} - 0 to 3 occurrences of an optional whitespace and a digit
$ - end of string.

JS demo:

var strs = ['+256897845','+1 232321','+29 2343 2432 43','+555 2356897845','+1245 2356878','+918989784578'];
var rx = /^\+(?=(?:\s?\d){7,17}$)\d+(?:\s?\d+){0,3}$/;
for (var s of strs) {
  console.log(s, "=>", rx.test(s));
}

score 0 · Answer 2 · answered Oct 14 '18 at 09:58

Although Wiktor's regex perfectly does the job, but I personally prefer to keep the regex simple as it will be more maintainable in case regex requirement changes which often happens.

You can write a function like this, this will not only take care of multiple spaces present anywhere but also hyphen (and other special characters) as that is also commonly present in mobile numbers and finally you can simply apply this regex /^[+]\d{7,13}$/

Demo here,

     function isValidMobileNumber(number) {
     if (number == null || number.trim().length == 0) {
      return false;
     }
     number = number.replace(new RegExp('[ -]', 'g'), '');
     var rx = /^[+]\d{7,13}$/;
     return rx.test(number);
    }
    
    var strs = ['+1-234-242-2434','+1-23-2','+123','+256897845','+1 232321','+29 2343 2432 43','+555 2356897845','+1245 2356878','+918989784578'];
    for (var s of strs) {
     console.log (s + " --> " + isValidMobileNumber(s));
    }

Regular Expression for phone number including country code maximum 18 character

2 Answers2