How to merge two WordPress categories without losing SEO

Step by step

1. Choose which category survives

Compare the two archives in Search Console: Performance → Search results, filter by Page for each archive URL, and look at clicks and impressions over several months. Keep the one with more traffic and links. If they are even, keep the shorter, clearer slug. Note the full URL of the one you will delete, including its parent if it is a child category.

2. Check your permalink structure

Open Settings → Permalinks. If the structure contains %category%, a post's URL includes one of its categories, and removing a category can change post addresses. In that case, list the affected posts first and plan redirects for them, or set each post's primary category deliberately; see choosing the category in post URLs. With /%postname%/ or a date-based structure, post URLs are not affected at all.

3. Add the keeper to every post

1. Go to Posts → All Posts.
2. Choose the category you are removing in the category dropdown and click Filter.
3. Raise the rows per page under Screen Options if needed, tick the header checkbox to select all, choose Edit from Bulk actions and click Apply.
4. In the Bulk Edit panel, tick the category you are keeping in the Categories box.
5. Click Update.

Bulk Edit adds the ticked category to the selected posts. It does not remove the old one, which the next step handles. Repeat for each page of results.

4. Move the description and settings worth keeping

Open both categories under Posts → Categories. If the one being deleted has a better description, copy the useful parts into the keeper. Do the same for its SEO title and meta description: open the term, click Hydrogen SEO → Edit SEO settings and compare. Anything stored on the deleted term goes with it.

5. Delete the spare category

Under Posts → Categories, hover the spare category and click Delete. WordPress states what happens: deleting a category does not delete its posts, and posts that were only in that category are moved to the default category. Since every post already has the keeper, none fall back to "Uncategorized". If the deleted category had child categories, they move up a level, and their URLs change with them.

6. Redirect the old archive

The deleted archive now returns 404. In Hydrogen SEO → Redirections, click Add New:

• From URL: /category/email/
• Match Type: Starts With, so paged addresses such as /category/email/page/2/ and the archive's feed are covered too.
• To URL: /category/email-marketing/
• Redirect Type: 301 - Permanent Redirect

One caution with Starts With: the comparison ignores the trailing slash, so /category/email/ also matches /category/email-marketing/ itself if the keeper's slug begins with the deleted one, which would loop. When the slugs overlap like that, use Exact Match for the archive and add a second exact rule for any paged URL that has traffic.

7. Verify and tidy links

curl -sI https://example.com/category/email/ | grep -iE "^HTTP|^location"

Expect a single 301 to the keeper. Then update menus that pointed at the old category (WordPress removes a deleted category's menu item, so check for gaps), and fix links typed into posts. Open the keeper's archive and confirm the post count went up.

Merging tags, or a tag into a category

Tags work the same way: add the keeper tag in Bulk Edit by typing it into the Tags field, then delete the spare under Posts → Tags. Tags have no default, so nothing is reassigned on deletion. To turn tags into categories or the reverse in bulk, Tools → Import lists a Categories and Tags Converter that you install from that screen. Either way the old archive URL needs its own redirect.

When not to merge

Keep two categories when they serve different searches and each has enough posts to be a useful page. Overlap in a few posts is normal, since a post can sit in both. If one of the two is merely thin, and you do not want its posts mixed into the other, noindexing that archive is the lighter option; see noindex tag and category archives.