Best regular expression for phone number that accepts many variations

Here is a handy regular expression that will accept many variations of an U.S. phone number, allowing the input to be somewhat flexible.

^\s*[(]?\d{3}[).\-]?\s*\d{3}(\s*|[.\-]?)\d{4}\s*$

// accepted
8015551212
801 555 1212
(801)5551212
801.555.1212
801.555-1212
801-555-1212
(801)555-1212
(801) 555-1212
801-555.1212
(801 555 1212
(801 555 1212
801)5551212

// rejected
8015551212a
80155512122
801a5551212
8015;551212
(801))5551212

Better regular expression for phone numbers (multiple formats)

I'm often surprised at how often websites only accept a specific format for phone number input (U.S.) so I thought I would post a more flexible input format.

We want to allow users to enter phone numbers in formats like:

(123) 456-7890
123-456-7890
123.456.7890
1234567890

Using a regular expression, we can allow all these formats and more.

^\s*[(]?(?<AreaCode>\d{3})[)]?(\s*|[.-])(?<Prefix>\d{3})(\s*|[.-])?(?<LineNumber>\d{4})\s*$

Notice that we specify regular expression group names to easily pick up the phone number parts. In C#, this can be done like:

Code:

string prefix = match.Groups["Prefix"].Value;

Finally, here the some C# code to kick things off.

Code:

Regex rePhone = new Regex(@"^\s*[(]?(?<AreaCode>\d{3})[)]?(\s*|[.-])(?<Prefix>\d{3})(\s*|[.-])?(?<LineNumber>\d{4})\s*$");
Match match = rePhone.Match("123.456.7890");
Console.WriteLine(match.Success);