Successful bloggers know the importance of learning SEO concepts. One method of measuring the SEO health of your website is to calculate the ratio of your pages in Google’s supplemental index.

What is the supplemental index?

In short, its nickname is ‘Google Hell’ and it is a place your website does not want to be. The supplemental index is a secondary index for lower ranking pages. Pages found in the supplemental index tend to be crawled less often and will never be assigned Page Rank. As a result, these pages tend to appear lower in organic search results. There are many reasons why pages lose rank and fall into the supplemental index. Here are the most common:

  • Low quality content (1 line posts)
  • Internal duplicate content noise or scraped posts
  • Lack of external links
  • The number of query string parameters exceeds Google’s algorithm

Calculating your supplemental index ratio

There has been numerous posts in the SEO community on calculating Google supplemental index ratios. Unfortunately, most of the queries to determine the number of pages in the supplemental index were deprecated and no longer return the correct results. These queries include:

  • *** -sjpked
  • *** -sljktf
  • *** -view
  • *** -ndsfoiw

Since supplemental queries seem to have a limited lifetime, a more stable way is to find the number of pages in the main index (those that have a higher chance of appearing in search results) and subtract it from the total number of pages indexed.

Total Pages Indexed =
Pages in the Main Index =

Pages in Supplemental Index = Total Pagex Indexed – Pages in the Main Index

To calculate your supplemental index ratio you simply divide the number of supplemental pages by the total number of pages indexed (the lower this ratio, the better). Below you will find some examples:

Website Pages in Supplemental Index Total Pages Indexed Supplemental Index Ratio 90 2260 3,9% 60 521 11,5% 116 574 20,2%

How can I make my ratio better?

  1. Optimize Your Blog for Search Engines. Many tips can be found in the previous article Blog Setup: 40 Practical Tips
  2. QC + QL = No Supplemental Index. The best way to pull your pages out of the supplemental index is by providing quality content (QC) that will get you quality links (QL). Search engines will start to view your blog as an authority and will place your page in the main index. You might get lucky and through internal linking or site association other pages may also be removed from the supplemental index.
  3. Be patient. New blogs tend to have ratios above 75% for a number of months. This is because of low traffic and a lack of quality links. Keep posting quality content and your ratio will improve.

Calculate Your Google Supplemental Index Ratio