What is Google’s Secondary Index?

There is a secondary index in Google that contains pages that Google considers less important. They are displayed on search engine results pages only when no pages from the primary index match the queried search terms. The free Supplemental Index Ratio Calculator from mapelli.info shows you what percentage of your indexed pages are considered to be supplemental by Google. The lower the percentage is, the more likely your pages will show up in query results.

How Does the Supplemental Index Calculator Work?

The tool works by finding the total number of Google indexed pages from your website and the pages found in the main index. It calculates the percentage by dividing the number of main index pages by the number of total pages. A low percentage means that most all of your website pages are found in the main index.

To lower the Supplemental Index Ratio, you can increase the number of inbound links, and avoid duplicate content and extend the length of your posts or articles. You also want to avoid too many reciprocal links and links from “bad neighborhoods”, or those considered by Google to be spam sites, to be considered relevant by Google’s robots.