PHP | gmp_gcd() Function Last Updated : 11 Jul, 2025 Comments Improve Suggest changes Like Article Like Report The gmp_gcd() is an in built function in PHP which is used to calculate the GCD of 2 GMP numbers (GNU Multiple Precision : For large numbers). Syntax: gmp_gcd ( $num1, $num2 ) Parameters: This function accepts two GMP numbers $num1 and $num2 as parameters. This function calculates the GCD of these two numbers. Return Value: This function returns a positive GMP number which is the GCD of $num1 and $num2. Examples: Input : gmp_gcd("12", "21") Output : 3 Input : gmp_gcd("15", "30") Output : 15 Explanation: In the above example gmp_gcd() function calculates the greatest common divisor of num1 and num2. The result is always positive even if either of, or both, input operands are negative. Below programs illustrate the gmp_gcd() function in PHP. Program 1: PHP <?php $gcd = gmp_gcd("12", "21"); echo gmp_strval($gcd) . "\n"; ?> Output: 3 Program 2: PHP <?php $gcd = gmp_gcd("15", "30"); echo gmp_strval($gcd) . "\n"; ?> Output: 15 Reference: https://www.php.net/manual/en/function.gmp-gcd.php Comment S Shubham_Singh_29 Follow 0 Improve S Shubham_Singh_29 Follow 0 Improve Article Tags : Misc Web Technologies PHP PHP-math Explore PHP Tutorial 8 min read BasicsPHP Syntax 4 min read PHP Variables 5 min read PHP | Functions 8 min read PHP Loops 4 min read ArrayPHP Arrays 5 min read PHP Associative Arrays 4 min read Multidimensional arrays in PHP 5 min read Sorting Arrays in PHP 4 min read OOPs & InterfacesPHP Classes 2 min read PHP | Constructors and Destructors 5 min read PHP Access Modifiers 4 min read Multiple Inheritance in PHP 4 min read MySQL DatabasePHP | MySQL Database Introduction 4 min read PHP Database connection 2 min read PHP | MySQL ( Creating Database ) 3 min read PHP | MySQL ( Creating Table ) 3 min read PHP AdvancePHP Superglobals 6 min read PHP | Regular Expressions 12 min read PHP Form Handling 4 min read PHP File Handling 4 min read PHP | Uploading File 3 min read PHP Cookies 9 min read PHP | Sessions 7 min read Like