Phone Number Validation Regular Expression

Phone number validation can follow the E.164 international format, which is the standard for international telephone numbering. E.164 numbers are formatted with a plus sign (+) followed by the country code and subscriber number, with a maximum of 15 digits total. Phone numbers are a specialized type of number pattern.

International Format (E.164)

^\+?[1-9]\d{1,14}$

Explanation

^ - Start of the string.
\+? - Optional plus sign (+) for international format.
[1-9] - First digit must be 1-9 (country codes cannot start with 0).
\d{1,14} - Followed by 1 to 14 additional digits (E.164 allows maximum 15 digits total).
$ - End of the string.

Implementation

const phoneRegex = /^\+?[1-9]\d{1,14}$/;
const isValidPhone = (phone) => phoneRegex.test(phone);

import re

def is_valid_phone(phone):
  phoneRegex = r"^\+?[1-9]\d{1,14}$"
  return re.match(phoneRegex, phone) is not None

use regex::Regex;

fn is_valid_phone(phone: &str) -> bool {
  let phoneRegex = Regex::new("^\+?[1-9]\d{1,14}$")
    .expect("Could not parse phone validation regex");
  phoneRegex.is_match(phone)
}

package main

import (
  "fmt"
  "regexp"
)

func isValidPhone(phone string) bool {
  phoneRegex := "^\+?[1-9]\d{1,14}$"
  re := regexp.MustCompile(phoneRegex)
  return re.MatchString(phone)
}

import Foundation

func isValidPhone(_ phone: String) -> Bool {
  let phoneRegex = "^\+?[1-9]\d{1,14}$"
  return NSPredicate(format: "SELF MATCHES %@", phoneRegex).evaluate(with: phone)
}

using System;
using System.Text.RegularExpressions;

class Application {
  static bool IsValidPhone(string phone) {
    string phoneRegex = "^\+?[1-9]\d{1,14}$";
    return Regex.IsMatch(phone, phoneRegex);
  }
}

import java.util.regex.*;

public class Application {
  public static boolean isValidPhone(String phone) {
    String phoneRegex = "^\+?[1-9]\d{1,14}$";
    Pattern pattern = Pattern.compile(phoneRegex);
    Matcher matcher = pattern.matcher(phone);
    return matcher.matches();
  }
}

<?php
function isValidPhone($phone) {
  $phoneRegex = "^\+?[1-9]\d{1,14}$";
  return (bool) preg_match("/" . $phoneRegex . "/", $phone);
}
?>

Test Cases

Phone Number	Valid
+12025550123
+441234567890
+33123456789
+861234567890
+61212345678
+81312345678
15551234567
+1
+

123
+01234567890
+123456789012345678
abc123456789
+1-202-555-0123
(202) 555-0123
202.555.0123

US/National Format

For validating US phone numbers in common national formats with optional parentheses, dashes, dots, or spaces as separators, you can use a more flexible pattern. This validates 10-digit US phone numbers in various formats.

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

Explanation

^ - Start of the string.
\(? - Optional opening parenthesis.
\d{3} - Exactly three digits (area code).
\)? - Optional closing parenthesis.
[-.\s]? - Optional separator: dash, dot, or space.
\d{3} - Exactly three digits (central office code).
[-.\s]? - Optional separator: dash, dot, or space.
\d{4} - Exactly four digits (line number).
$ - End of the string.

Implementation

const nationalPhoneRegex = /^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$/;
const isValidPhone = (phone) => nationalPhoneRegex.test(phone);

import re

national_phone_regex = r'^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$'

def is_valid_phone(phone):
    return bool(re.match(national_phone_regex, phone))

use regex::Regex;

fn is_valid_phone(phone: &str) -> bool {
    let re = Regex::new(r"^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$").unwrap();
    re.is_match(phone)
}

package main

import (
    "fmt"
    "regexp"
)

func isValidPhone(phone string) bool {
    phoneRegex := "^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$"
    re := regexp.MustCompile(phoneRegex)
    return re.MatchString(phone)
}

import Foundation

func isValidPhone(_ phone: String) -> Bool {
    let phoneRegex = "^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$"
    return NSPredicate(format: "SELF MATCHES %@", phoneRegex).evaluate(with: phone)
}

using System;
using System.Text.RegularExpressions;

class Program {
    static bool IsValidPhone(string phone) {
        return Regex.IsMatch(phone, @"^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$");
    }
}

import java.util.regex.*;

public class Application {
    public static boolean isValidPhone(String phone) {
        return Pattern.matches("^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$", phone);
    }
}

<?php
function isValidPhone($phone) {
    return (bool) preg_match("/^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$/", $phone);
}

Test Cases

Phone Number	Valid
2025550123
(202)5550123
(202) 555-0123
202-555-0123
202.555.0123
202 555 0123
(202)555-0123
+12025550123
123

12345
(202) 555-012
202-555-012
abc-def-ghij
202-555-01234