Should you noindex category pages?
I see this question come up a lot in regards to WordPress, but the situation would be similar no matter what CMS you might be using.
It depends on how you are using your categories. Most sites I see are using categories as part of their navigation or a sub-navigation. In those cases, you absolutely should not noindex the category pages.
Different people from Google have said slightly different things in regards to this, but there are two messages we have heard pretty consistently over the past few years.
First, if you noindex category pages, Google will likely treat them as soft 404s eventually. Not a huge deal, but it can trigger errors in Search Console. Just be aware of that.
Second, over time, if you noindex category pages, Google will treat the links on those pages as nofollow. This is why I say it depends how you are using your category pages. If you have links pointing to your category pages (like you would if you use them in any type of navigation menu), you are pushing link equity into those pages, but nothing is coming back out of those pages. You are bleeding link equity.
This can harm the internal link structure of your site.
Simple rule of thumb: Do you have category pages that visitors might land on by following a link somewhere on your site? If the answer to that question is “yes”, then do not noindex them.
If there is no way for visitors to find your category pages other than through your sitemap or by typing the URL directly into their browser, then it does not really matter if you noindex them or not.
Objections:
I often hear people say that they do not want to index their category pages for 1 of 2 reasons:
Reason 1 – The page is low quality and full of nothing but duplicate content.
Solution: Then make your category pages into something useful. Build them out more. Include some static content on the pages and not just nothing but post excerpts.
Reason 2 – A category page is outranking the primary page they want to rank for a keyword.
Solution: Do a better job optimizing your target page. It should not be difficult to outrank your own category page. Or push them both up higher and get them both ranking highly.