Title: wp_generate_uuid4 Published: December 6, 2016 Last modified: February 24, 2026 --- # wp_generate_uuid4(): string ## In this article * [Return](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#return) * [Source](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#source) * [Related](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#related) * [Changelog](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#changelog) * [User Contributed Notes](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#user-contributed-notes) [ Back to top](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#wp--skip-link--target) Generates a random UUID (version 4). ## 󠀁[Return](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#return)󠁿 string UUID. ## 󠀁[Source](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#source)󠁿 ```php function wp_generate_uuid4() { return sprintf( '%04x%04x-%04x-%04x-%04x-%04x%04x%04x', mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0x0fff ) | 0x4000, mt_rand( 0, 0x3fff ) | 0x8000, mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ), mt_rand( 0, 0xffff ) ); } ``` [View all references](https://developer.wordpress.org/reference/files/wp-includes/functions.php/) [View on Trac](https://core.trac.wordpress.org/browser/tags/6.9.4/src/wp-includes/functions.php#L7958) [View on GitHub](https://github.com/WordPress/wordpress-develop/blob/6.9.4/src/wp-includes/functions.php#L7958-L7970) ## 󠀁[Related](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#related)󠁿 | Used by | Description | | [WP_Application_Passwords::create_new_application_password()](https://developer.wordpress.org/reference/classes/wp_application_passwords/create_new_application_password/)`wp-includes/class-wp-application-passwords.php` | Creates a new application password. | | [WP_Application_Passwords::get_user_application_passwords()](https://developer.wordpress.org/reference/classes/wp_application_passwords/get_user_application_passwords/)`wp-includes/class-wp-application-passwords.php` | Gets a user’s application passwords. | | [WP_Customize_Manager::establish_loaded_changeset()](https://developer.wordpress.org/reference/classes/wp_customize_manager/establish_loaded_changeset/)`wp-includes/class-wp-customize-manager.php` | Establishes the loaded changeset. | | [WP_Customize_Manager::_publish_changeset_values()](https://developer.wordpress.org/reference/classes/wp_customize_manager/_publish_changeset_values/)`wp-includes/class-wp-customize-manager.php` | Publishes the values of a changeset. | | [WP_Customize_Manager::save_changeset_post()](https://developer.wordpress.org/reference/classes/wp_customize_manager/save_changeset_post/)`wp-includes/class-wp-customize-manager.php` | Saves the post for the loaded changeset. | | [WP_Customize_Manager::save()](https://developer.wordpress.org/reference/classes/wp_customize_manager/save/)`wp-includes/class-wp-customize-manager.php` | Handles customize_save WP Ajax request to save/update a changeset. | | [WP_Customize_Manager::__construct()](https://developer.wordpress.org/reference/classes/wp_customize_manager/__construct/)`wp-includes/class-wp-customize-manager.php` | Constructor. | [Show 2 more](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#) [Show less](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#) ## 󠀁[Changelog](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#changelog)󠁿 | Version | Description | | [4.7.0](https://developer.wordpress.org/reference/since/4.7.0/) | Introduced. | ## 󠀁[User Contributed Notes](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#user-contributed-notes)󠁿 1. [Skip to note 3 content](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#comment-content-6070) 2. [thanasisxan](https://profiles.wordpress.org/thanasisxan/) [ 4 years ago ](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/#comment-6070) 3. [You must log in to vote on the helpfulness of this note](https://login.wordpress.org?redirect_to=https%3A%2F%2Fdeveloper.wordpress.org%2Freference%2Ffunctions%2Fwp_generate_uuid4%2F%23comment-6070) Vote results for this note: 4[You must log in to vote on the helpfulness of this note](https://login.wordpress.org?redirect_to=https%3A%2F%2Fdeveloper.wordpress.org%2Freference%2Ffunctions%2Fwp_generate_uuid4%2F%23comment-6070) 4. It should be noted that using this function to generate uuid’s **WILL** lead to collisions by creating duplicates, I found out not the fun way. 5. The function `mt_rand()` used will always produce the same sequence of random numbers given the same seed. So every time a seed is repeated, the same exact UUID is generated. 6. To get around this, you would need to seed it using something else for example: 7. ```php mt_srand( crc32( serialize( array( microtime( true ), 'USER_IP', 'ETC' ) ) ) ); ``` 8. [Log in to add feedback](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fdeveloper.wordpress.org%2Freference%2Ffunctions%2Fwp_generate_uuid4%2F%3Freplytocom%3D6070%23feedback-editor-6070) 9. [Skip to note 4 content](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/?output_format=md#comment-content-5371) 10. [Philipp Stracker](https://profiles.wordpress.org/strackerphil-1/) [ 5 years ago ](https://developer.wordpress.org/reference/functions/wp_generate_uuid4/#comment-5371) 11. [You must log in to vote on the helpfulness of this note](https://login.wordpress.org?redirect_to=https%3A%2F%2Fdeveloper.wordpress.org%2Freference%2Ffunctions%2Fwp_generate_uuid4%2F%23comment-5371) Vote results for this note: 1[You must log in to vote on the helpfulness of this note](https://login.wordpress.org?redirect_to=https%3A%2F%2Fdeveloper.wordpress.org%2Freference%2Ffunctions%2Fwp_generate_uuid4%2F%23comment-5371) 12. Sample result: 11223344-5566-7788-99AA-BBCCDDEEFF00 13. A UUID represents a 128-bit value (16 bytes): It contains four 4-byte digits that are represented in hex notation, and are segmented by 4 “-” symbols. The total length is 36 characters. 14. The “-” symbols appear after byte 4, byte 6, byte 8 and after byte 10. 15. Because it’s a hex-value, a UUID should be treated in a case-insensitive manner: ` 11223344-5566-7788-99AA-BBCCDDEEFF00` is identical to `11223344-5566-7788-99aa- bbccddeeff00` 16. This function always returns a lower-case string. 17. To get a 32-character string (same as MD5) you could use: 18. ```php