Regex to allow only this format 123-456-7890

Question

i am looking for a regex to accept only this number not any other format.

123-456-7890

I have tried this but accepting diff formats as well.

Regex regexPhoneNumber = new Regex(@"^\(?([0-9]{3})\)?[-. ]?([0-9]{3})[-. ]?([0-9]{4})$");

@WiktorStribiżew, I didn't know there is an issue with .NET and `\d`s. Could you share? — ndnenkov, May 25 '17 at 12:38
@ndn Unlike in Ruby, .NET `\d` [matches all Unicode digits by default](https://stackoverflow.com/a/16621778/3832970). — Wiktor Stribiżew, May 25 '17 at 12:39

score 1 · Accepted Answer · answered May 25 '17 at 12:39

You may use

Regex regexPhoneNumber = new Regex(@"\A[0-9]{3}-[0-9]{3}-[0-9]{4}\z");

It will accept a string that starts with 3 digits, then has -, then 3 digits, -, and then 4 digits followed with the very end of string position.

Details:

\A - start of string
[0-9]{3} - 3 ASCII digits
- - a hyphen
[0-9]{3} - 3 digits
- - again a hyphen
[0-9]{4} - 4 digits
\z - the very end of the string (no final newline can follow, as is the case with $ anchor).

Note that in case you want to use \d instead of [0-9] to shorten the pattern, and still match ASCII only digits, pass RegexOptions.ECMAScript option to the Regex object.

Regex to allow only this format 123-456-7890

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