Validating UK phone number (Regex C#)

Question

public static bool ValidatePhoneNumber(string number)
{
    return Regex.Match(number, "^(\+44\s?7\d{3}|\(?07\d{3}\)?)\s?\d{3}\s?\d{3}$", RegexOptions.IgnoreCase).Success;
}

This is what I have but I get errors saying Unrecognized escape sequence. Can anbody help? needs to be able to have +44.

Related: http://stackoverflow.com/questions/6582309/regex-for-all-uk-telephone-numbers — Soner Gönül, Aug 06 '14 at 08:53
possible duplicate of [A comprehensive regex for phone number validation](http://stackoverflow.com/questions/123559/a-comprehensive-regex-for-phone-number-validation) — Alexander, Aug 06 '14 at 08:53
Take a look at http://derekslager.com/blog/posts/2007/09/a-better-dotnet-regular-expression-tester.ashx as well as testing it lets you enter the unescaped RegEx and then gives you the C# equivalent string — Liath, Aug 06 '14 at 09:05

Rahul Tripathi · Accepted Answer · 2014-08-06T09:01:14.133

15

You may try this regex if you are trying to get it with +44

^(((\+44\s?\d{4}|\(?0\d{4}\)?)\s?\d{3}\s?\d{3})|((\+44\s?\d{3}|\(?0\d{3}\)?)\s?\d{3}\s?\d{4})|((\+44\s?\d{2}|\(?0\d{2}\)?)\s?\d{4}\s?\d{4}))(\s?\#(\d{4}|\d{3}))?$

This will match for

+447222555555 | +44 7222 555 555 | (0722) 5555555 #2222

REGEX DEMO

You can try this regex for UK phone numbers:

/^\(?0( *\d\)?){9,10}$/

This regex will check for 10 or 11 digit numbers which are there in UK numbers, starting with a 0, which may have formatting spaces between any of the digits, and optionally a set of brackets for the area code.

Also in your regex you need to add @ to get rid of that error(Unrecognized escape sequence):

public static bool ValidatePhoneNumber(string number)
{
   return Regex.Match(number, @"^(\+44\s?7\d{3}|\(?07\d{3}\)?)\s?\d{3}\s?\d{3}$", RegexOptions.IgnoreCase).Success;
}

edited Aug 06 '14 at 09:01

answered Aug 06 '14 at 08:49

Rahul Tripathi

168,305
31
280
331

this is not working with `+44`, which was a requirement – EaterOfCode Aug 06 '14 at 08:53
The top one does not work for a ten-digit number 0123456789 – VictorySaber Jun 30 '17 at 12:59
1

@niico The number 07999999999 passes using the first and last regex's in this answer. – Mark Jul 26 '18 at 14:31

score 7 · Answer 2 · answered Jul 23 '15 at 13:55

7

This is a pretty solid regex, will handle area codes, extension numbers and the +44 international code as well as mobile numbers and even 10 digit numbers:

^(?:(?:\(?(?:0(?:0|11)\)?[\s-]?\(?|\+)44\)?[\s-]?(?:\(?0\)?[\s-]?)?)|(?:\(?0))(?:(?:\d{5}\)?[\s-]?\d{4,5})|(?:\d{4}\)?[\s-]?(?:\d{5}|\d{3}[\s-]?\d{3}))|(?:\d{3}\)?[\s-]?\d{3}[\s-]?\d{3,4})|(?:\d{2}\)?[\s-]?\d{4}[\s-]?\d{4}))(?:[\s-]?(?:x|ext\.?|\#)\d{3,4})?$

answered Jul 23 '15 at 13:55

RattyLaa

323
3
12

3

This seems a pretty comprehensive regex pattern that matches all valid UK telephone formats listed here: [area-codes.org.uk](http://www.area-codes.org.uk/formatting.php) My tests can be found here: [regex101.com](https://regex101.com/r/f0HaLr/3) – AndySX Sep 22 '17 at 10:33

user3913543 · Answer 3 · 2014-08-06T09:04:30.857

2

Try using this:

^(\+44\\s?7\\d{3}|\(?07\\d{3}\)?)\\s?\\d{3}\\s?\\d{3}$

In order for the regex to recognize the \s, \d, etc you need to put double slash \\. If not you'll get an illegal escape character error.

edited Aug 06 '14 at 09:04

answered Aug 06 '14 at 08:58

user3913543

21
3

score 1 · Answer 4 · answered Dec 07 '17 at 11:06

1

This works well and allows 3 and 4 digit extensions. It also ensures that only mobile numbers are entered. UK mobile numbers start with 07 regardless of the provider

^(\+44\s?7\d{3}|\(?07\d{3}\)?)\s?\d{3}\s?\d{3}(\s?\#(\d{4}|\d{3}))?$

answered Dec 07 '17 at 11:06

Francis Benyah

567
7
11

score 0 · Answer 5 · answered Apr 13 '19 at 09:24

Try this code,

    using System.Text.RegularExpressions; 
    public static bool CheckNumber(string strPhoneNumber)
    {
            string MatchNumberPattern = "^\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$";
            if (strPhoneNumber != null)
            {
                return Regex.IsMatch(strPhoneNumber, MatchNumberPattern);
            }
            else
            {
                return false;
            }
     }

Hope, this code helps you.

Validating UK phone number (Regex C#)

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