RegEx for valid international mobile phone number

Question

I use Clickatell to send SMSes to clients' mobile phones.

Is there a standardised regular expression for all valid mobile phone numbers, e.g. +27 123 4567? I'd roll my own, but I'm worried about missing an obscure, valid phone number format.

Answer 1

After stripping all characters except '+' and digits from your input, this should do it:

^\+[1-9]{1}[0-9]{3,14}$

If you want to be more exact with the country codes see this question on List of phone number country codes

However, I would try to be not too strict with my validation. Users get very frustrated if they are told their valid numbers are not acceptable.

Answer 2

Even if you write a regular expression that matches exactly the subset "valid phone numbers" out of strings, there is no way to guarantee (by way of a regular expression) that they are valid mobile phone numbers. In several countries, mobile phone numbers are indistinguishable from landline phone numbers without at least a number plan lookup, and in some cases, even that won't help. For example, in Sweden, lots of people have "ported" their regular, landline-like phone number to their mobile phone. It's still the same number as they had before, but now it goes to a mobile phone instead of a landline.

Since valid phone numbers consist only of digits, I doubt that rolling your own would risk missing some obscure case of phone number at least. If you want to have better certainty, write a generator that takes a list of all valid country codes, and requires one of them at the beginning of the phone number to be matched by the generated regular expression.

Answer 3

Posting a note here for users looking into this into the future. Google's libphonenumber is what you most likely would want to use. There is wrappers for PHP, node.js, Java, etc. to use the data which Google has been collecting and reduces the requirements for maintaining large arrays of regex patterns to apply.

Answer 4

Even though it is about international numbers I would want the code to be like :

/^(\+|\d)[0-9]{7,16}$/;

As you can have international numbers starting with '00' as well.

Why I prefer 15 digits : http://en.wikipedia.org/wiki/E.164

Answer 5

// Regex - Check Singapore valid mobile numbers

public static boolean isSingaporeMobileNo(String str) {
    Pattern mobNO = Pattern.compile("^(((0|((\\+)?65([- ])?))|((\\((\\+)?65\\)([- ])?)))?[8-9]\\d{7})?$");
    Matcher matcher = mobNO.matcher(str);
    if (matcher.find()) {
        return true;
    } else {
        return false;
    }
}

Answer 6

^\+[1-9]{1}[0-9]{7,11}$ 

The Regular Expression ^\+[1-9]{1}[0-9]{7,11}$ fails for "+290 8000" and similar valid numbers that are shorter than 8 digits.

The longest numbers could be something like 3 digit country code, 3 digit area code, 8 digit subscriber number, making 14 digits.