SEO Monday – Google's Primary and Supplemental Index: Where Do Your Pages Stand

By Joe


Welcome to your Daily Concept from Exclusive Concepts – Today is SEO Monday. As a reminder, don’t forget to subscribe to our daily video series by signing up at

My name is Scott, an SEO Analyst at Exclusive Concepts, and today I’ll be talking about Google’s primary versus supplemental index and how to determine what pages of your site fall in which index.

As some of you may already know, Google’s index is actually comprised of two tiers: a primary, or high quality index and a supplemental, or secondary index. The liberties of having a webpage in Google’s primary index is that it is more visible in search results and grants you the potential to rank for more competitive terms. Pages that fall within this index are usually high in quality, which means they have unique content and the site owner has clearly put in the time and effort to make sure the page is unique and worth indexing.

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Lower quality pages fall into the supplemental index. These are usually pages that aren’t as high in quality, meaning they don’t have unique content, they share the same page title as other pages on the site, or they lack enough content for engines to consider it a high quality page. Falling into this index allows you to still be found for longer tail search terms, but the visibility isn’t as strong as in the primary index.

In addition to these two indexes, there is also the possibility of your pages not being indexed at all. This usually occurs when the quality of your content is so poor that Google decides not to waste any of its bandwidth by putting you in either index, or when Google’s spiders cannot find your page at all due to poor navigation on your site.

So how do you determine where your pages fall within Google’s two indexes? Well luckily, there are a few queries to help you determine which pages are in the primary versus supplemental index, and which pages aren’t indexed at all.

The first query I’ll show is how to determine how many pages of your site are in the overall index. This can be done with the simple “site:” command and entering your URL after the semicolon. For example, let’s say we wanted to find out how many of CNN’s pages were in the overall index. We would do this by entering site: in Google’s search field.

Now that we’ve found the total number of pages in the overall index, which includes both the primary and supplemental, we can now run a query to see just the pages in the primary index. We do this by performing the same command, but this time adding an asterisk after the forward slash at the end of the URL as shown (site:*).

We can see that there are much less pages in the primary index compared to the overall index.

So how do we determine how many pages are in the supplemental index. Well, one easy way to figure it out is by subtracting the total number of pages in the index from the number of primary pages we just searched for. However, if you’d like to see which pages fall into the supplemental index, you can do so by using a more advanced query as shown (site: -site:*).

Finally, the last thing we want to determine is how many pages of your site aren’t in Google’s index at all. This can be determined by estimating the total number of pages on your site and subtracting the total number of indexed pages from our first search query from this number.

So now that we’ve figured out where you pages fall within Google’s index, what actions can you take to make sure as many pages as possible are within the primary index? One important step to take is to make sure all of your pages have enough unique content to be considered of high quality for the index. Once you’ve addressed the content issue, you’ll also want to make sure that the search engine spiders can easily find your pages through easy navigation. For ecommerce site owners, this means having your category and subcategory pages accessible within 1-2 clicks from the homepage and product pages within 3-4 clicks of the homepage to help encourage spiderability.

If you have any problems with your pages not being indexed or falling into Google’s supplemental index, please feel free to give us a call or fill out an audit request. That’s all for this week’s edition of SEO Monday and I hope you’ve found it helpful for your business! Please tune in tomorrow for another enticing edition of PPC Tuesday!