PHP: Validation of US Phone Numbers

Validating phone numbers is a crucial aspect of web development, ensuring that user inputs conform to the required format. In this article, we will explore how to validate US phone numbers using PHP.

US Phone Number Format

US phone numbers generally follow these formats:

• (123) 456-7890
• 123-456-7890
• 123.456.7890
• 1234567890
• +1 123-456-7890

Our goal is to validate these formats while rejecting invalid inputs.

PHP Function for Validation

We will use regular expressions (regex) to check if the input matches the valid US phone number patterns. Below is the PHP function for validation:

function validateUSPhoneNumber($phoneNumber) {
    // Define the regex pattern for US phone numbers
    $pattern = '/^(\+1\s?)?(\(?\d{3}\)?[\s.-]?)?\d{3}[\s.-]?\d{4}$/';

    // Check if the phone number matches the pattern
    if (preg_match($pattern, $phoneNumber)) {
        return true;
    } else {
        return false;
    }
}

Usage Example

Here’s how you can use the function in your PHP code:

$testNumbers = [
    "(123) 456-7890",
    "123-456-7890",
    "123.456.7890",
    "1234567890",
    "+1 123-456-7890",
    "123-45-6789" // Invalid
];

foreach ($testNumbers as $number) {
    if (validateUSPhoneNumber($number)) {
        echo "$number is valid.\n";
    } else {
        echo "$number is invalid.\n";
    }
}

Sample Output

(123) 456-7890 is valid.
123-456-7890 is valid.
123.456.7890 is valid.
1234567890 is valid.
+1 123-456-7890 is valid.
123-45-6789 is invalid.

If you need stricter validation, consider verifying the number format against real-world constraints, such as checking the validity of area codes or using third-party APIs for phone number validation.