Regex for North American Phone Number Validation

In this regex tutorial, we will learn to validate user-entered phone numbers for a specific format (in this example phone numbers are formatted in North American format) and if the numbers are correct then reformat them to a standard format for display. I have tested formats including 1234567890, 123-456-7890, 123.456.7890, 123 456 7890, (123) 456 7890, and all such combinations.

1. Using Regex to Validate North American Phone Numbers

Regex : ^\\(?([0-9]{3})\\)?[-.\\s]?([0-9]{3})[-.\\s]?([0-9]{4})$

The above regular expression can be used to validate all formats of phone numbers to check if they are valid North American phone numbers.

List phoneNumbers = new ArrayList();
phoneNumbers.add("1234567890");
phoneNumbers.add("123-456-7890");
phoneNumbers.add("123.456.7890");
phoneNumbers.add("123 456 7890");
phoneNumbers.add("(123) 456 7890");
 
//Invalid phone numbers
phoneNumbers.add("12345678");
phoneNumbers.add("12-12-111");
 
String regex = "^\\(?([0-9]{3})\\)?[-.\\s]?([0-9]{3})[-.\\s]?([0-9]{4})$";
 
Pattern pattern = Pattern.compile(regex);
 
for(String email : phoneNumbers)
{
  Matcher matcher = pattern.matcher(email);
  System.out.println(email +" : "+ matcher.matches());
}

The program output:

1234567890 :    true
123-456-7890 :    true
123.456.7890 :    true
123 456 7890 :    true
(123) 456 7890 :  true
 
12345678 :      false
12-12-111 :     false

2. Using Regex to Format a North American Phone Number

Regex : ($1) $2-$3

Use the above regex to reformat phone numbers validated in the above step to reformat in a consistent way to store/display purposes.

List phoneNumbers = new ArrayList();
phoneNumbers.add("1234567890");
phoneNumbers.add("123-456-7890");
phoneNumbers.add("123.456.7890");
phoneNumbers.add("123 456 7890");
phoneNumbers.add("(123) 456 7890");
 
//Invalid phone numbers
phoneNumbers.add("12345678");
phoneNumbers.add("12-12-111");
 
String regex = "^\\(?([0-9]{3})\\)?[-.\\s]?([0-9]{3})[-.\\s]?([0-9]{4})$";
 
Pattern pattern = Pattern.compile(regex);
 
for(String email : phoneNumbers)
{
  Matcher matcher = pattern.matcher(email);
  //System.out.println(email +" : "+ matcher.matches());
  //If phone number is correct then format it to (123)-456-7890
  if(matcher.matches())
  {
     System.out.println(matcher.replaceFirst("($1) $2-$3"));
  }
}

The program output:

(123) 456-7890
(123) 456-7890
(123) 456-7890
(123) 456-7890
(123) 456-7890

The above regex will work in JavaScript as well. So keep these regex handy when you need them next time.

Happy Learning !!