A meta description tag in HTML is basically a summarized snippet of the content of a web page. The usual length that Google allows these web pages is approximately 160 characters. Different search engines use these snippets when they provide the search results to give the users a sneak peek in the content of the page before they open it.
A recent study by Portent which examined search results for 30,000 keywords has found out that 70% of the times, Google rewrites these meta descriptions. It means that when a web page writes a meta description for its content when it is presented on the Google search results page, Google ends up rewriting the meta description.
For search results in mobile, Google rewrites meta descriptions at a rate of 71%, and for search results on desktop, the rate of rewriting is around 68%.
Hardly 30% of the time Google uses the meta description that a page provides, otherwise, around 70% of the time, it just ignores them.
According to Google’s John Mueller, there can be three reasons for Google’s rewriting of the meta descriptions.
The web page did not properly summarize the page content and did not use the meta description properly.
To match the web page content more accurately with the search query if the meta description by the web page is missing some important part of the search query.
Google is maybe trying to match the search query with the content, but the match is not in the meta description provided by the web page.
Now, data from this recent study suggests several ways this meta description rewriting occurs or is seen by Google.
If the meta description rewrite rate is considered according to the position of the web page appearing in the search results on the first page, Portent noticed that the first three search results have the highest click-through rate. So, to bring the search results on 4th, 5th, and 6th positions to prominence too, it seems that Google rewrites their meta descriptions more. So, it means that meta descriptions are more likely to be rewritten based on where they are positioned in the Google search result page.
The second thing that Portent’s study highlighted was that if there is a search query that has a higher search volume, or if there is a web page that has a higher search volume, meaning that it appears in the search results mostly, Google does not rewrite its meta descriptions more.
So, it seems that the higher the search volume, the fewer chances of Google to rewrite the meta description.
It can be because of the priority of SEOs that they write meta descriptions for keywords that appear in most searches per month.
Another important factor that Portent’s study highlighted is that on desktop, Google chooses to display 156-165 characters in a meta description. If there is a date, then the snippet’s characters can reduce to 142.
When Google rewrites the meta description, it gives itself some more room than what it allows the web page content writers and owners and displays 160-167 characters, and with dates, its rewritten meta descriptions have 147-149 characters.
On mobile, the meta description length goes up to 118-121 characters, and with dates, it is around 95-105 characters.
But when Google rewrites a meta description on mobile, it chooses to display around 114-120 characters, and with dates, the length of these meta descriptions can go up to 99-105 characters.
Portent recommends that to improve SEO, webmasters and publishers should try to keep these meta descriptions between 150-160 characters-long for regular pages. While for blog posts, the length should be kept somewhere around 138-148 characters.
Portent also suggests that the most relevant and important information must come in the first 100 characters.