Google’s site: search operator does not actually hit Google’s live database. So, if you are looking to see how many pages (or which pages) are indexed in the Google search engine results, don’t rely on the site:domain.com search operator.
Let’s take a look at specific “proof” that this is occurring. The first screen shot below is using the site:dnaccess.com search operator. The second screen shot is searching for the brand name.
Both the screen shots above were done within about 30 seconds of each other. As you can see, the site:dnaccess.com search query shows the title tag and results from the “for sale” landing page at DAN. The domain name was previously listed for sale until I acquired the domain name this week. The domain name has been owned by the same person since around 2000 I believe, and it’s always had a for sale landing page on it (thus Google hasn’t crawled and indexed it often).
I think it’s pretty significant that a site:domain.com search is not hitting the Google “live results” database, as in the past many have relied on this search operator (including myself) to get an idea of how many pages of a website are actually indexed in Google’s search engine results pages. There are some uses for the site: search operator, such as looking to see how large a website is: I will do that search to estimate how large a website is before I commit to a technical audit of a website. There would be a price difference between me auditing a 20 page website versus a 500,000 page website.
The bottom line is that we cannot rely on the site: search operator anymore, as it’s not hitting the Google “live” database of search engine results. It’s still helpful, though, in certain case such as site:dnaccess.com “domain name” whereas I would want to find pages on my site that Google thinks are about a certain keyword (domain name) so I can maybe link to that page in a blog post.
If you’re looking for a better way to see which pages are crawled and indexed, you’ll need to use Google Search Console, under the Indexing/Pages section.