Convert some categories to a custom taxonomy

Category and Tag are two default WordPress taxonomies which help you to group posts together easily. You also can create custom taxonomy to group your contents.

If you want to convert some categories (or tags) to a new taxonomy. Here are steps to do:

I. Register a new taxonomy

Firstly, you need to register a new taxonomy.
You can do that easily with this plugin Custom Post Type UI.
Or you also can use the register_taxonomy() function.

II. Convert specific categories to new taxonomy

There are 2 possible ways to convert:

1. Convert automatically

   Please install and use this plugin Taxonomy Switcher.
   This is the recommended way to convert quickly, easily, and safety.

2. Convert manually

   Or you can convert manually with below steps:

• Add terms to the new taxonomy

  

• Move posts from a category to new taxonomy term

  The quickest way is:

  + In WordPress admin Posts page, select a specific category, then click “Filter” button to show all matching posts:

  + Select the top checkbox, select the “Edit” option in the “Bulk Actions” dropdown, then click “Apply” button:
  

  + Select the desired term of the new taxonomy:

  

  then click the “Update” button.

  Repeat this step for each category you want to convert.

• Remove converted categories (optionally)

  After above steps, you might remove categories which are already converted to (replaced by) new taxonomy.

Best regards,