Last updated on December 15, 2009. Tags: category list, WordPress category ID
Category IDs are numerical values that WordPress assigned to all categories. Each category has a unique category ID. While you can change the name, description and slug of a category anytime, you cannot change the ID assigned to a category unless you edit the database, which is not advisable unless you really know how to do it.
If you are using WordPress' default URL structure, the category ID can be found at the end of the category page's URL. It's in the form of http://domain.com/?cat=1; in this example, 1 is the category ID.
If you configured your permalinks in a way that the category ID is not visible in the URL, you can still see it in your dashboard. Click on the "Categories" link under the "Posts" header to open the add/edit category interface shown below. Then you can get the category ID by hovering the mouse pointer on that category in the category list and checking the number at the end of your status bar.

Knowing the category ID can be useful in some WordPress tweaks and customization such as preventing certain categories from showing in the category list.
Posted by Greten on November 29, 2009 under Definition, WordPress tweaks
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