Simple Way to Validate Phone Numbers in PHP

Last Updated Jan 10, 2022
Emma Jagger

Engineer, maker, Google alumna, CMU grad

Table of Contents:

In today’s world, assuring real sign-ups is critical for your business. Without genuine registrations, your marketing campaign will fail miserably. Email address validation is a popular way of verifying real sign-ups. But phone number validation works as an extra layer of security. It helps you to prevent fraudulent activities effectively. In this post, you will find a simple way of validating phone numbers using PHP code. We also have other similar guides, for geolocating IP addresses using PHP and validating email addresses using PHP.

Don't reinvent the wheel.
Abstract's APIs are production-ready now.

Abstract's suite of API's are built to save you time. You don't need to be an expert in email validation, IP geolocation, etc. Just focus on writing code that's actually valuable for your app or business, and we'll handle the rest.

Get started for free

How to validate phone number in PHP

The easiest way to create a PHP validate phone number function is using inbuilt PHP filters.

However, developers around the world are preferring to use regular expressions. PHP provides powerful functions for parsing regular expressions. So, you can validate phone number with different types of formats effectively.

To validate phone number using regular expression, you have to follow these steps:

1. Create the function

Create a PHP validate phone number function, called validating(), with a parameter of $phone.


function validating($phone){

2. Create the statement

Then you have to create an if/else statement for determining whether the given phone number is valid or not. Let’s say that the genuine phone number is 10 digits long, ranging from 0 to 9. To perform the validation, you have to utilize this regular expression: /^[0-9]{10}+$/. Also, you have to use the reg_match() function.


if(preg_match('/^[0-9]{10}+$/', $phone)) {
echo "Valid Phone Number";
} else {
echo "Invalid Phone Number";
}

If the given telephone number matches the specified regular expression, it will print “Valid Phone Number.” Otherwise, it will print “Invalid Phone Number” as the error message.

3. Call the function

Now, let’s try verifying different phone numbers by calling our validating() function for number validation in PHP:


validating("1016660180"); //10 digits valid phone number
validating("101666018000"); //12 digits invalid phone number
validating("101$666*01"); //10 letters phone number with invalid characters
validating("101$666*0180"); //10 digits phone numbers with invalid characters

4. You will see this output:


Valid Phone Number
Invalid Phone Number
Invalid Phone Number
Invalid Phone Number

Overall, the following code will look like this:


function validating($phone){
if(preg_match('/^[0-9]{10}+$/', $phone)) {
echo " Valid Phone Number";
} else {
echo " Invalid Phone Number";
}
}
validating("1016660180"); //10 digits valid phone number
validating("101666018000"); //12 digits invalid phone number
validating("101$666*01"); //10 letters phone number with invalid characters
validating("101$666*0180"); //10 digits phone numbers with invalid characters

That’s it! You have learned the way of validating phone numbers in PHP using regular expressions. The same rules apply to mobile number validation.

Format variation of phone numbers

Phone numbers have different formats. So, verifying them could have been really challenging. Fortunately, using a PHP function has made the process very simple.

As said earlier, the in-built PHP filter can make it easier for you to validate phone number. Here, you will use it to validate numbers with different formats.  

Cell phones

1. First, you have to create a function, called validating().


function validating($phone){

2. Create a variable, called valid_number. It will have the filter_var() function with a FILTER_SANITIZE_NUMBER_INT constant.


$valid_number = filter_var($phone, FILTER_SANITIZE_NUMBER_INT);

3. Now, you can print the valid_number variable.


echo $valid_number.;
}

4. Finally, let’s call the validating() PHP function with for mobile number validation.


validating("101-666-0260");

You will see this output: 101-666-0260

Overall, the code will look like this:


function validating($phone){
  $valid_number = filter_var($phone, FILTER_SANITIZE_NUMBER_INT);
  echo $valid_number.;
}
validating("101-666-0260");

That’s how you validate a cell phone number with the in-built PHP filter.

Special characters

A phone number can have certain characters, like + and -. But what will happen if the user enters the number incorrectly with special characters, like $ and *? You need to find a way to filter them out.

By using filter_var() function, you can strip them off from the given phone number.

Let’s try validate a phone number that contains $ and *, like this: 101$777*0280

Let’s use this code:


function validating($phone){
  $valid_number = filter_var($phone, FILTER_SANITIZE_NUMBER_INT);
  echo $valid_number.;
}
validating("101$777*0280");

You will see an output with $ and * being removed from the given phone number: 1017770280

International numbers

International phone numbers start with + with some also needing the area code. So, you need to figure out a way to prevent it from being filtered out. Fortunately, filter_var() function supports the + sign. So, you will never have to worry about it being stripped off.

Let’s try performing something for international users, for example an Indian phone number validation. The number looks like this: +91-202-5555-0234

As you can see, the country code of India is +91. How will filter_var() function react if an Indian phone number is entered? Will it filter out the + sign?

Let’s use this code to figure out what happens:


function validating($phone){
  $valid_number = filter_var($phone, FILTER_SANITIZE_NUMBER_INT);
  echo $valid_number.;
}
validating("+91-202-5555-0234");

You will see an output like this: +91-202-5555-0234

As you can see, the filter_var() function supports the + sign. So, it’s not being filtered out.

Validation phone number with an API

By using APIs, you can validate phone numbers effortlessly. They come with all the necessary functions for verification. You just need to enter the number. The API will handle the rest. You don’t have to write any code from scratch. So, you can validate the phone numbers effortlessly.

You can try using Abstract’s phone number validation and verification API. It is reliable, blazing-fast, and easy to maintain. It can help you to validate phone numbers effortlessly.

Let’s use Abstract’s Phone Number Validation and Verification API to validate this phone number: 14154582468.


https://phonevalidation.abstractapi.com/v1/
  ? api_key = YOUR_UNIQUE_API_KEY
  & number = 14154582468

If the phone number request is successful, you will see this output:


{
  "number": "14154582468",
  "is_valid_number": true,
  "local_format":"4154582468",
  "international_format": "+14154582468",
  "country_name": "United States of America",
  "country_code": "US",
  "country_prefix":"+1",
  "registered_location": "San Francisco, CA",
  "carrier":"Verizon USA",
  "line_type": "Mobile",
}

The given phone number is valid, as the "is_valid_number" field is set to “true.” Also, it provides you with a variety of geolocation data, including country name and registered location of the phone number. You can utilize this information to enhance your marketing strategy.

As you can see, you don’t have to write any code from scratch. There is no need to utilize regular expressions or PHP in-built functions. You just need to get the API key and enter the phone number that you want to verify. Abstract’s Phone Number Validation and Verification API will handle the rest.

Wrapping up

That’s how you validate phone numbers using PHP procedural programming. You can use regular expressions or PHP in-built functions. However, the easiest way is to utilize a verification API. It will help you to validate the phone numbers effortlessly.

Validate phone numbers using Abstract's API

Get started for free
Validate phone numbers using Abstract's API
Get started