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How to check Whether a Variable is Null in PHP?

Last Updated : 21 Apr, 2025

We are given a variable and the task is to check whether the value of the given variable is null or not and returns a Boolean value using PHP.

To check a variable is null or not, we use is_null() function. A variable is considered to be NULL if it does not store any value. It returns TRUE if the value of variable $var is NULL, otherwise, returns FALSE.

Syntax:

boolean is_null( $var )

Example: This example checks whether a variable is null in PHP or not.

PHP

<?php 
// PHP Program to check whether 
// a variable is null or not?

$var1 = NULL; 
$var2 = "\0"; // "\0" means null character 
$var3 = "NULL"; 

// $var1 has NULL value, so always give TRUE 
is_null($var1) ? print_r("True\n") : print_r("False\n"); 

// $var2 has '\0' value which consider as null in 
// c and c++ but here taken as string, gives FALSE 
is_null($var2) ? print_r("True\n") : print_r("False\n"); 

// $var3 has NULL string value so it will false 
is_null($var3) ? print_r("True\n") : print_r("False\n"); 

?>

Output:

True
False
False

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