 # Factorial Program in PHP | PHP Tutorial

## What is factorial?

Factorial says to multiply all whole numbers from the chosen number down to 1. The factorial symbol is “!”

For examples:

```4! = 4 × 3 × 2 × 1 = 24
7! = 7 × 6 × 5 × 4 × 3 × 2 × 1 = 5040```

Factorial program in PHP. Here we would love to share with you how to calculate or find the factorial of any number in PHP.

Here we will take the some of the examples for find or calculate the factorial of any number in PHP like a factorial program in PHP using a loop, factorial program in PHP using recursion, an factorial program in PHP using the form

### Factorial Program in PHP

Here we will learn how to calculate factorial of any number. There are two methods to calculate the factorial of any number in PHP.

• Using loop
• factorial program in PHP using loop
• factorial program in PHP using the form
• Using recursive method
• factorial program in PHP using recursion

### Using loop

#### Factorial program in PHP using loop

Here we will create a PHP program to find or calculate factorial of number 5 using the for loop in PHP.

```<?php
// define variable and assign value, which you want to find factorial
\$num = 5;

//define variable, which you want to store factorial number value
\$factorial = 1;

//iterate the loop
for (\$i=1; \$i <= \$num; \$i++) {

\$factorial = \$factorial * \$x;
}
// display the factorial of number
echo "Factorial of \$num is \$factorial";
?>
```

#### Factorial program in PHP using the form

Here we will create a PHP program to find or calculate the factorial of any number using PHP form.

```<html>
<title>Factorial using Form in PHP</title>
<body>
<form action="<?php echo htmlspecialchars(\$_SERVER["PHP_SELF"]); ?>" method="post">
Enter the Number:<br>
<input type="number" name="number" id="number">
<input type="submit" name="submit" value="Submit" />
</form>
<?php
if(\$_POST){
\$fact = 1;
//getting value from input text box
\$number = \$_POST['number'];
echo "Factorial of \$number:<br><br>";
//start loop
for (\$i = 1; \$i <= \$number; \$i++){
\$fact = \$fact * \$i;
}
echo \$fact . "<br>";
}
?>
</body>
</html>
```

### Using recursive method

#### factorial program in PHP using recursion

Here we will create a PHP program to find or calculate factorial of any number using the recursion in PHP.

```<?php
function factorial(\$n)
{
if(\$n <= 1)
{
return 1;
}
else
{
return \$n * factorial(\$n - 1);
}
}

echo "Factorial of 6 is " .factorial(6);
?>
```