How Long Should Your Meta Description Be? (2018 Edition)
Summary: The end of November saw a spike in the average length of SERP snippets. Across 10K keywords (90K results), we found a definite increase but many oddities, such as video snippets. Our data suggests that many snippets are exceeding 300 characters, and going into 2018 we recommend a new meta description limit of 300 characters.
How Long Should Your Meta Description Be? (2018 Edition)
Back in spring of 2015, we reported that Google search snippets seemed to be breaking the 155-character limit, but our data suggested that these cases were fairly rare. At the end of November, RankRanger's tools reported a sizable jump in the average search snippet length (to around 230 characters). Anecdotally, we're seeing many long snippets in the wild, such as this 386-character one on a search for "non compete agreement":
Search Engine Land was able to get confirmation from Google of a change to how they handle search snippets, although we don't have specifics or official numbers. Is it time to revisit our guidelines on meta descriptions limits heading into 2018? We dug into our daily 10,000-keyword tracking data to find out...
The trouble with averages
In our 10K tracking data for December 15th, which consisted of 89,909 page-one organic results, the average display snippet (stripped of HTML, of course) was 215 characters long, slightly below RankRanger's numbers, but well above historical trends.
This number is certainly interesting, but it leaves out quite a bit. First of all, the median character length is 186, suggesting that some big numbers are potentially skewing the average. On the other hand, some snippets are very short because their meta Ddescriptions are very short. Take this snippet for Vail.com:
Sure enough, this is Vail.com's meta description tag (I'm not gonna ask):
Do we really care that a lot of people just write ridiculously short meta descriptions? No, what we really want to know is at what point Google is cutting off long descriptions. So, let's just look at the snippets that were cut (determined by the " ..." at the end). In our data set, this leaves just about 3.6% (3,213), so we can already see that the vast majority of descriptions aren't getting cut off.
Coincidentally, the average is still 215, but let's look at the frequency distribution of the lengths of just the cut snippets. The graph below shows cut-snippet lengths in bins of 25 (0-25, 25-50, etc.):
If we're trying to pin down a maximum length for meta descriptions, this is where things get a bit weird (and frustrating). There seems to be a chunk of snippets cut off at the 100–125 character range and another chunk at the 275–300 range. Digging in deeper, we discovered that two things were going on here...
Oddity #1: Video snippets
Spot-checking some of the descriptions cut off in the 100–125 character range, we realized that a number of them were video snippets, which seem to have shorter limits:
These snippets seem to generally max out at two lines, and they're further restricted by the space the video thumbnail occupies. In our data set, a full 88% of video snippets were cut off (ended in " ..."). Separating out video, only 2.1% of organic snippets were cut off.
Oddity #2: Pre-cut metas
A second oddity was that some meta description tags seem to be pre-truncated (possibly by CMS systems). So, the "..." in those cases is an unreliable indicator. Take this snippet, for example:
This clocks in at 150 characters, right around the old limit. Now, let's look at the meta description:
This Goodreads snippet is being pre-truncated. This was true for almost all of the Goodreads meta descriptions in our data set, and may be a CMS setting or a conscious choice by their SEO team. Either way, it's not very useful for our current analysis.
So, we attempted to gather all of the original meta description tags to check for pre-truncated data. We were unable to gather data from all sites, and some sites don't use meta description tags at all, but we were still able to remove some of the noise.
Let's try this again (...)
So, let's pull out all of the cut snippets with video thumbnails and the ones where we know the meta description ended in "...". This cuts us down to 1,722 snippets (pretty deep dive from the original 89,909). Here's what the frequency distribution of lengths looks like now:
Now, we're getting somewhere. There are still a few data points down in the 150–175 range, but once I hand-checked them, they appear to be sites that had meta description tags ending in "..." that we failed to crawl properly.
The bulk of these snippets are being cut off in the 275–325 character range. In this smaller, but more normal-looking distribution, we've got a mean of 299 characters and a median of 288 characters. While we've had to discard a fair amount of data along the way, I'm much more comfortable with these numbers.
What about the snippets over 350 characters? It's hard to see from this graph, but they maxed out at 375 characters. In some cases, Google is appending their own information:
While the entire snippet is 375 characters, the "Jump..." link is added by Google. The rest of the snippet is 315 characters long. Google also adds result counts and dates to the front of some snippets. These characters don't seem to count against the limit, but it's a bit hard to tell, because we don't have a lot of data points.
Do metas even matter?
Before we reveal the new limit, here's an uncomfortable question — when it seems like Google is rewriting so many snippets, is it worth having meta description tags at all? Across the data set, we were able to successfully capture 70,059 original Meta Description tags (in many of the remaining cases, the sites simply didn't define one). Of those, just over one-third (35.9%) were used as-is for display snippets.
Keep in mind, though, that Google truncates some of these and appends extra data to some. In 15.4% of cases, Google used the original meta description tag, but added some text. This number may seem high, but most of these cases were simply Google adding a period to the end of the snippet. Apparently, Google is a stickler for complete sentences. So, now we're up to 51.3% of cases where either the display snippet perfectly matched the meta description tag or fully contained it.
What about cases where the display snippet used a truncated version of the meta description tag? Just 3.2% of snippets matched this scenario. Putting it all together, we're up to almost 55% of cases where Google is using all or part of the original meta description tag. This number is probably low, as we're not counting cases where Google used part of the original meta description but modified it in some way.
It's interesting to note that, in some cases, Google rewrote a meta description because the original description was too short or not descriptive enough. Take this result, for example:
Now, let's check out the original meta description tag...
In this case, the original meta description was actually too short for Google's tastes. Also note that, even though Google created the snippet themselves, they still cut it off with a "...". This strongly suggests that cutting off a snippet isn't a sign that Google thinks your description is low quality.
On the flip side, I should note that some very large sites don't use meta description tags at all, and they seem to fare perfectly well in search results. One notable example is Wikipedia, a site for which defining meta descriptions would be nearly impossible without automation, and any automation would probably fall short of Google's own capabilities.
I think you should be very careful using Wikipedia as an example of what to do (or what not do), when it comes to technical SEO, but it seems clear from the data that, in the absence of a meta description tag, Google is perfectly capable of ranking sites and writing their own snippets.
At the end of the day, I think it comes down to control. For critical pages, writing a good meta description is like writing ad copy — there's real value in crafting that copy to drive interest and clicks. There's no guarantee Google will use that copy, and that fact can be frustrating, but the odds are still in your favor.
Is the 155 limit dead?
Unless something changes, and given the partial (although lacking in details) confirmation from Google, I think it's safe to experiment with longer meta description tags. Looking at the clean distribution, and just to give it a nice even number, I think 300 characters is a pretty safe bet. Some snippets that length may get cut off, but the potential gain of getting in more information offsets that relatively small risk.
That's not to say you should pad out your meta descriptions just to cash in on more characters. Snippets should be useful and encourage clicks. In part, that means not giving so much away that there's nothing left to drive the click. If you're artificially limiting your meta descriptions, though, or if you think more text would be beneficial to search visitors and create interest, then I would definitely experiment with expanding.