Factorial of a number in php

(Last Updated On: 19/01/2024)

In today’s blog, we’ll understand the concept of the Factorial of a number in PHP. How to find factorial of number in PHP with example. 

What is a Factorial Program with an example?

A factorial program calculates the product of all positive integers up to a given number. The iterative method is straightforward; nevertheless, the recursive approach offers an elegant solution to compute factorials. Below is an example of a factorial program in PHP:

function calculateFactorial($number) {
    return $number <= 1 ? 1 : $number * calculateFactorial($number - 1);

$result = calculateFactorial(5); // Example: Calculate factorial of 5
echo "Factorial: " . $result;

Elevate Your PHP Skills with a Treasure Trove of Fibonacci Series in PHP!

Find Factorial of Number Using recursion in PHP

For the below code, you’ll understand how to find the factorial of number using recursion in PHP:

// Factorial of a number in php
function factorial($num)  
  if($num <= 1) {  
	return 1;  
	return $num * factorial($num - 1);  

$num = 11;  
echo "Factorial of $num is " .factorial($num); /*Call the Function */

Explanation of the code:

1. Function Definition:

The function `factorial` takes a parameter `$num`.

Inside the function, it checks if `$num` is less than or equal to 1. If true, it returns 1.

If false, it recursively multiplies `$num` by the result of the factorial of `$num – 1`.

2. Function Call:

The code sets the variable `$num` to 11.

It then calls the `factorial` function with `$num` as an argument and echoes the result.

3. Output:

The output will be “Factorial of 11 is 39916800”, where the calculated value is the factorial of 11.

Know the Fibonacci series in javascript using recursion here!


Factorial of 11 is 39916800

Moreover, the recursive nature of the function elegantly represents the factorial calculation, providing a clear and concise solution.

Find Factorial of Number Using for Loop in PHP

The code mentioned below will help you to understand the concept of ‘how to find the factorial of number using recursion in PHP’.

// Factorial of a number in php
$num= 6;

$f = 1;

/*Iterate the loop to find the factorial.*/
for ($i=1; $i <= $num; $i++) {  
  $f = $f * $i;  
/*Display the output.*/
echo "Factorial of $num is $f";  

Explanation of the code:

1. Initialization:

`$num` is set to the number for which the factorial needs to be calculated, in this case, 6.

`$f` is initialized to 1, as the factorial of any number starts with 1.

2. For Loop:

The for loop runs from `$i = 1` to `$i <= $num`.

In each iteration, `$f` is multiplied by the loop variable `$i`.

This process continues until the loop reaches the desired number.

3. Calculation:

The loop effectively calculates the factorial of the given number by multiplying the current factorial value (`$f`) with the loop variable (`$i`).


Factorial of 6 is 720

In this specific example with `$num = 6`, the output would be “Factorial of 6 is 720,” as 6! (6 factorial) is equal to 720.

Real-life Application of Factorial Number

There are many practical uses for the factorial of a number, particularly in situations where permutations and combinations are involved. Check out a few instances:

1. Combinatorial Analysis:

In combinatorial mathematics, factorials are frequently used to determine how many permutations or combinations there exist for a given collection of components. Factorials are useful in determining possible outcomes, for example, when organizing or selecting things from a set.

2. Probability Calculations:

Factorials are used in probability theory to determine the total number of favourable events. For calculating probabilities in situations where order counts, this is essential.

3. Statistics:

Factorials are used in statistical computations, including probability distribution computations involving combinations and arrangements.

4. Algorithm Optimization:

Factorials serve a purpose in algorithms and optimization approaches in computer science. Factorials, for instance, can be used to optimize specific computations in recursive or dynamic programming techniques.

5. Genetics and Biology:

Factuals are used in genetics to determine the total number of potential genetic permutations and combinations. To comprehend and forecast genetic effects, this is crucial.

6. Queueing Theory:

In the field of queueing theory, factorials are used to analyze and model systems involving queues, such as predicting wait times and optimizing service processes.

7. Engineering Design:

Factorials are utilized in engineering design and optimization, especially in scenarios where arrangements or combinations of elements are critical.

Factorials are an effective tool for a variety of problem-solving applications, and their comprehension and application are fundamental to many areas of mathematics, computer science, and scientific research.

We hope you are able to understand the concept of the ‘Factorial of a number in PHP’ with Newtum. For more such informative blogs and coding courses check out our website Newtum.

Once to learn the concept you can execute code on the Newtum PHP online compiler. Learn, experiment, and execute your code effortlessly with Newtum. 

Factorial of number in php- FAQ

1. What is the factorial of a number in PHP?

A: The factorial of a number in PHP is the product of all positive integers up to that number. It is calculated using loops or recursion in PHP programming.

2. How is the factorial calculated using recursion in PHP?

A: Recursion is a technique where a function calls itself. In PHP, the factorial of a number can be calculated recursively by multiplying the number with the factorial of (number – 1) until the base case is reached.

3. Can you explain the importance of the factorial program in real-life scenarios?

A: Yes, factorials find applications in combinatorial mathematics, probability calculations, statistics, genetics, and more. They are essential for determining permutations, and combinations, and predicting outcomes in various fields.

4. What is the difference between calculating factorial using recursion and a loop in PHP?

A: Recursion involves a function calling itself, making the code concise but potentially leading to stack overflow for large inputs. A loop iterates through the numbers, providing better performance for large factorials but with more code.

5. How can I use the Newtum Online Compiler to practice factorial programs in PHP?

A: Newtum Online Compiler offers a platform to write, execute, and experiment with PHP code. You can use it to practice and test your factorial programs, gaining hands-on experience in PHP programming.

About The Author