How to find Sum the Digits of a given Number in PHP ?

We will explore how to find the sum of the digits of a given number in PHP. This task involves extracting each digit from the number and adding them together to get the final sum.

Using a loop to extract digits one by one

In this approach, we are using a for loop to iterate over each character in the digit. First, we will convert the number to a string to easily access each digit. Then we will iterate over each character in the string. Convert each character back to a number and add it to a running sum.

Example: The below example uses for loop to to find the sum of the digits of a given number in PHP.

PHP

<?php
  
   // function to calculate sum of digits
    function sumDigits($number) {
        $sum = 0;
        // converting number to string to access digits easily
        $numberStr = (string)$number;
        for ($i = 0; $i < strlen($numberStr); $i++) {
            $digit = (int)$numberStr[$i];
            $sum += $digit;
        }
        return $sum;
    }

    $number = 12345;
    echo "Sum of digits: " . sumDigits($number);

?>

Output

Sum of digits: 15

Using mathematical operations to extract digits

In this approach, we are using mathematical operations to calculate sum of digits of numbers. First we use modulus operator (%) to extract the last digit of the number then add that extracted digit to a running sum. Then divide the number by 10 to remove the last digit. We will repeat the above steps until the number becomes 0.

Example: This example uses mathematical operations to find the sum of the digits of a given number in PHP.

PHP

<?php
    function sumDigits($number) {
        $sum = 0;
        while ($number != 0) {
            $digit = $number % 10;
            $sum += $digit;
            $number = (int)($number / 10);
        }
        return $sum;
    }

    $number = 76534;
    echo "Sum of digits: " . sumDigits($number);
?>

Output

Sum of digits: 25