WordPress Taxonomy: Complete Guide to Categories, Tags & Custom Taxonomies

Organizing content efficiently is crucial for both user experience and site management purposes. And for WordPress sites, taxonomies play a pivotal role by grouping related content together.

This guide covers the concept of WordPress taxonomies, explores the default options, and provides a step-by-step approach to creating custom taxonomies.

What is a taxonomy in WordPress?

In simple terms, a taxonomy is a way to group and classify content. It helps you organize posts, pages, and custom content types into meaningful groupings, making it easier for:

• Visitors to navigate your site
• Search engines to understand your content structure
• Your team to manage new and existing content

Think of taxonomies as labels or buckets that allow you to sort your website content.

Default taxonomies in WordPress

WordPress includes two main built-in taxonomies by default:

1. Categories

• Broad groupings that allow for hierarchical organization.
• For example, a blog about food might have categories for Breakfasts, Dinners, and Snacks, with sub-categories under each for Vegetarian, Meal Prep, and Slow Cooker.

2. Tags

• Non-hierarchical labels that describe specific attributes of content.
• A post in the Recipes category might have tags like Vegan, Vegetarian, and Gluten-Free.

Why should you create custom taxonomies?

While the default WordPress taxonomies are useful in many situations, they may not be sufficient for all websites. Here are common reasons to create custom taxonomies in WordPress:

1. Improve content organization

For sites with a lot of content, custom taxonomies make navigating and organizing information much easier. Unlike default categories and tags, you can create custom taxonomies around specific use cases based on your unique content.

For instance, a book review website might need to classify content based on Author, Publisher, or Publication Year rather than relying solely on broad categories like Fiction and Nonfiction.

2. Enhance usability for visitors

A well-structured site improves engagement by allowing visitors to find relevant content faster. If an online store enables filtering by Brand, Material, or Product Type, customers can navigate inventory more efficiently.

Similarly, a travel blog could use taxonomies such as Destination, Travel Style, and Budget Range to help people discover relevant articles.

3. Enhance custom post types

For sites that use specialized post types, custom taxonomies become even more useful.

A real estate listing website, for example, may use custom post types for Properties and define taxonomies like Property Type, Neighborhood, and Price Range. Without these specialized taxonomies, content organization would be much less intuitive.

4. Improve content filtering and search

When a website includes large volumes of information, the ability to filter content efficiently is crucial. Custom taxonomies allow for advanced filtering, making it easier for people to sort through content based on specific parameters.

Ecommerce sites, recipe databases, and directory websites particularly benefit from this setup.

5. Improve search engine optimization

Custom taxonomies can contribute to better search engine optimization (SEO) by creating more descriptive URLs, improving internal linking, and enabling highly-targeted content segmentation.

When properly configured, custom taxonomies help search engines understand the structure of a website and how pieces of content relate to one another, resulting in better indexing and rankings. For example, a movie review site could generate SEO-friendly URLs like /reviews/action-movies/ instead of just /reviews/.

6. Avoid over-reliance on categories and tags

Default categories and tags may seem sufficient, but overusing them can lead to disorganization. Tags often become cluttered and inconsistent when used without a structured plan.

Custom taxonomies ensure that content is classified in a consistent, scalable way, reducing redundancy and improving overall site management.

7. Boost multilingual and international sites

On multilingual websites, custom taxonomies can segment content based on language or region, improving the user experience for global audiences. For instance, an international news website could use taxonomies like Region or Language to help visitors immediately find content relevant to their location.

How to add custom WordPress taxonomies

There are two main ways to add custom taxonomies to your WordPress site: manually with code and using a plugin. Below, we’ll cover both methods so you can choose what works best for your website.

Method 1: How to add custom taxonomies with code

To create a custom taxonomy manually, you’ll need to add some code to your theme’s functions.php file. Make sure you’re either editing a child theme or using a code snippets plugin to avoid overwriting your work when you update your theme.

1. Open your functions.php file

• Access your function.php file via FTP or through your host’s file manager.
• Navigate to wp-content/themes/your-child-theme/functions.php.

Read this guide for full details on editing the functions.php file.

2. Add the custom taxonomy code

Below is an example of how to create a custom taxonomy called Genre for a custom post type called Books:

function register_book_genre_taxonomy() {

    $labels = array(

        'name'              => 'Genres',

        'singular_name'     => 'Genre',

        'search_items'      => 'Search Genres',

        'all_items'         => 'All Genres',

        'parent_item'       => 'Parent Genre',

        'parent_item_colon' => 'Parent Genre:',

        'edit_item'         => 'Edit Genre',

        'update_item'       => 'Update Genre',

        'add_new_item'      => 'Add New Genre',

        'new_item_name'     => 'New Genre Name',

        'menu_name'         => 'Genre',

    );

    $args = array(

        'hierarchical'      => true, // Set to false for non-hierarchical (like tags)

        'labels'            => $labels,

        'show_ui'           => true,

        'show_admin_column' => true,

        'query_var'         => true,

        'rewrite'           => array('slug' => 'genre'),

    );

    register_taxonomy('genre', array('books'), $args);

}

add_action('init', 'register_book_genre_taxonomy');

Here’s an explanation of the elements of this code:

• Register_taxonomy(): The WordPress function that creates the taxonomy
• ‘Genre’: The taxonomy’s internal name
• ‘Books’: The custom post type it applies to (replace with “post” for regular posts)
• ‘Hierarchical’: True makes it like categories (with parent/child relationships); false makes it like tags
• ‘Labels’: Defines how the taxonomy appears in the WordPress dashboard
• ‘Rewrite’: Sets the URL slug (e.g. yoursite.com/genre/fiction)

3. Save and test

Upload the file and check your WordPress dashboard. You should see Genres under the Books menu.

Method 2: How to add custom taxonomies using a plugin

If coding isn’t your thing, plugins like Custom Post Type UI make it easy to create custom taxonomies without touching a line of code.

1. Install Custom Post Type UI

• Go to Plugins → Add New in your WordPress dashboard.
• Search for “Custom Post Type UI,” install, and activate it.

2. Create the Taxonomy

• Navigate to CPT UI → Add/Edit Taxonomies.
• Fill in the details:
  • Taxonomy Slug: The name/slug for the taxonomy URL
  • Plural Label: The plural name of the taxonomy (e.g. Actors)
  • Singular Label: The singular name of the taxonomy (e.g. Actor)
  • Attach to Post Type: Choose a post type linked to the taxonomy
• Configure any other optional settings
• Click Add taxonomy.

3. Test it out

Go to your post type in the dashboard and confirm that the new taxonomy appears properly.

How to manually associate custom taxonomies with custom post types

If you’re using custom post types, associate the custom taxonomy to the correct one with this code:

register_taxonomy( 'genre', array( 'movies' ), $args );

Here, ‘movies’ is the custom post type.

Managing custom taxonomies

Once created, you can manage custom taxonomies through the WordPress admin dashboard:

• Adding terms: Navigate to the custom taxonomy in your WordPress dashboard and add new terms as needed.
• Editing terms: You can edit or delete existing terms in a similar way to categories and tags.

Best practices for custom taxonomies

To use custom taxonomies effectively:

• Plan your structure: Before creating them, outline how taxonomies will organize your content and how they will relate to one another.
• Keep the user experience in mind: Make sure that your taxonomies genuinely help with navigation and content discovery.
• Limit the number: Avoid overwhelming visitors with too many taxonomies. Focus on those that add significant value.
• Stick to consistent naming conventions: Use clear and consistent names for taxonomies and their terms.

Enhance functionality with plugins

For those uncomfortable with coding, several plugins can assist with creating and managing custom taxonomies:

• Custom Post Type UI: Offers an interface for registering and managing custom taxonomies and post types
• Pods: Provides tools to create and extend custom taxonomies, post types, and fields
• TaxoPress: Helps manage taxonomies, including creating custom ones and editing terms

Streamline taxonomy and content management with an AI assistant

Organizing content manually can be time-consuming, especially for large sites with extensive content libraries. This is where Jetpack AI Assistant can help.

Jetpack AI Assistant is a powerful AI-driven content creation tool that simplifies WordPress site management. It can assist with generating content, improving readability, and even suggesting taxonomy structures that align with your site’s goals. 

If you’re managing a site with custom taxonomies, Jetpack AI Assistant can help by:

• Generating optimized descriptions for taxonomy terms to improve the user experience and SEO
• Providing smart content recommendations based on your existing taxonomy structure
• Streamlining content categorization by suggesting relevant tags and categories for new posts
• Enhancing productivity by assisting in drafting and refining taxonomy-based pages efficiently

By integrating Jetpack AI Assistant into your workflow, you can maintain a well-structured site while focusing on content quality and user engagement. Try Jetpack AI Assistant today to bring intelligent automation to your WordPress site.

Frequently asked questions

What is the difference between a WordPress taxonomy and a term?

A taxonomy is the system you use to group posts together. A term is a single item inside that taxonomy. For example, “Category” is a taxonomy. “News” and “Updates” are terms inside the “Category” taxonomy.

Think of a taxonomy as a box for organizing things. The terms are the labels you put on the items inside that box. You have two default taxonomies in WordPress: Categories and Tags. You can also create your own custom taxonomies, such as “Author” for a book review site.

What is the difference between a hierarchical and non-hierarchical taxonomy?

A hierarchical taxonomy works with levels of importance. It allows you to have a main group and smaller groups inside it. This is the parent and child relationship. Categories are the best example of this. You might have “Fruit” as a parent and “Apple” as a child.

A non-hierarchical taxonomy is flat. It has no levels or parents. Everything is equal. Tags are the best example of this structure. You use non-hierarchical taxonomies to label specific details that do not need to be in a strict order. You choose the type based on how you want to sort your data.

How many categories and tags should I use on a single post?

It is best to put each post in only one category. If you must use two, that is okay, but more than two can confuse search engines and visitors. One main category keeps your site structure clean.

For tags, there is no perfect number. A good rule is to add between three and ten tags that are very relevant to the post’s content. Do not add dozens of tags. This does not help with SEO. Use tags to describe the specific topics in the post, not to list every possible keyword.

Can taxonomies create duplicate content and hurt my SEO?

Yes, taxonomies can create duplicate content issues if you are not careful. This happens when the same post appears on multiple category or tag pages. It can also happen if your taxonomy archive pages show only short excerpts without any unique text.

Search engines may see these pages as low-quality. To prevent this, assign each post to only one primary category. You can also add unique introductory text to your most important category pages. For tag pages that are not very important, you can tell search engines not to index them.

When should I create a custom taxonomy instead of using categories?

You should create a custom taxonomy when categories and tags are not specific enough for your content. Categories are for broad topics. If you need a separate, special way to group content, a custom taxonomy is the right choice.

For instance, a movie review website could use a custom taxonomy called “Genre” with terms like “Action” and “Comedy”. A real estate website could use a custom taxonomy for “Location”. This helps visitors filter and find content in a way that makes sense for your specific subject matter.

How do I show my custom taxonomies on my website?

After you create a custom taxonomy, you can show it on your website in a few ways. Many WordPress themes will automatically show the terms associated with a post, usually near the title or at the end of the article. You can also add a list of all the terms from a custom taxonomy to your site’s sidebar using a widget.

For more advanced control, you can edit your theme’s template files. This lets you place the taxonomy terms exactly where you want them and style them to match your site’s design.

What is a taxonomy archive page and how do I make it better?

A taxonomy archive page is a page that WordPress automatically creates for each category or tag. It lists all the posts that belong to that term. By default, these pages can be simple and not very useful.

To make them better, you should add unique content. Go to the editor for a specific category or tag in your WordPress dashboard. Use the description box to write a helpful introduction about that topic. This text will appear at the top of the archive page, making it more valuable for both visitors and search engines.

Is it better to add custom taxonomies with a plugin or with code?

Using a plugin is better for most people because it is easy and you do not need to write any code. A plugin gives you a simple form to fill out to create your custom taxonomy. This method is fast and safe.

Adding code to your theme’s functions.php file is better for developers or users who need very specific options. The code method gives you full control over every setting. If you choose to use code, always use a child theme so you do not lose your changes when you update your main theme.

What are some common mistakes to avoid with WordPress taxonomies?

A common mistake is creating too many categories or tags. This makes a site messy. Another mistake is using very similar names for categories and tags, which can cause confusion. For example, having a category called “Baking” and a tag called “Bake” is not a good practice.

You should also avoid putting a single post in many different categories. This weakens your site structure. Finally, a big mistake is ignoring your taxonomy archive pages. Leaving them as simple lists of posts is a missed opportunity for both user experience and SEO.