One TaxoPress user asked us about using WordPress Categories. They wanted to know if there's a limit to the number of sub-categories they can create on their WordPress site. This ability to have a parent term is one key difference between Categories and Tags.
The simple answer is “No”. There is no technical limit to how deep your nested categories can go. In the image below, I've created 10 levels of categories:
You can keep adding sub-category levels as deep as you wish. The main limitation to consider will be the WordPress admin area which will start to look strained. In the image below, I've added twenty levels. When I go to add “Level 21”, the “Parent Category” dropdown appears to be broken.
In the next image, you can see how those extra levels appear on the main “Categories” screen. Each one is only displayed after a long row of hyphens.
And when you try to add a category to a post, you may find that the lower levels are not easily visible inside the metabox.
The reason that WordPress allows you to have an unlimited number of sub-categories is that these are simple database entries. The sub-categories are controlled by the
parent column in the
wp_term_taxonomy table. Adding more sub-categories will not slow your site down at all. Click here for more on the database structure of WordPress taxonomies.
Finally, I'll note that you can add multiple levels to any WordPress taxonomy. Go to the “Taxonomies” screen in TaxoPress. When you click “Edit”, you'll be able to change the settings for each taxonomy. You can control whether the taxonomy is organized in parent-child relationships.
If you do want to go many levels deep with sub-categories, it might be best to do it with an internal taxonomy where your regular user can learn to navigate the WordPress quirks mentioned in this post. You can use these categories to connect any post type, including Pages.