mid-century modern clock on blue wall
mid-century modern clock on blue wall

Understanding Misinterpreted Metrics: Session Duration

Tonya Davis


There are many different metrics that you can analyze and monitor in Google Analytics. This can be anything from goal conversions, to top channels, and even a user flow chart. There are however four main metrics that are the most common to watch; sessions, bounce rate, users, and finally session duration. 

All provide great insight on how users interact with your website and each can help you determine where improvements need to be made. However one metric in particular is commonly misconstrued: session duration. 

Session duration is a metric that reports the average amount of time a user spends on your website. That seems simple enough, so how come so many people get it wrong? To understand this, we will need to gain a better understanding of exactly how this metric works. 

<br />How is session duration calculated?

We should probably explain what a session is before we explain how session duration is calculated. A session is essentially a visit to your website. The session will begin once a user lands on your site and end once they leave or if they are inactive for over 30 minutes. 30 minutes is the default setting in Google Analytics, but this can be changed to be longer or shorter if needed. 

Now let’s examine how the average session duration is calculated. Here is the formula:

Total duration (in seconds) of all sessions during a set time period / Total number of sessions during that same time period.

Let’s look at an example: 

  • User #1 is on the site for 22 seconds
  • User #2 is on the site for 400 seconds
  • User #3 is on the site for 40 seconds
  • User #4 is on the site for 150 seconds

To calculate our average session duration using the above formula, we would add the duration of each individual session (22 + 400 + 40 + 150) and then divide the sum of that total (612) by the total number of sessions (4) to get an average session duration of 153 seconds or 2 minutes and 55 seconds.

Seems simple enough to understand, right? However this is where many people will start to misinterpret the session duration metric. 

Google will not know how long someone has spent on a page until a user has taken an action on said page. 

Let me explain. Say that a user enters your site and spends a good 3 minutes reading through the page. The user then clicks to a second page and spends another 5 minutes there before leaving the site. How much time would Google track for that session? Only 3 minutes. 

Google doesn’t count the exit page as part of the session because no action had been taken on that page. To be clear, an action is some form of engagement; a video play, link click, form fill, etc. 

Even if a user spent a good 15 minutes on that second page, unless they took some type of action, that time doesn’t get reported. 

This same rule applies to single page visits. If a user enters your site and then leaves without engaging, that’s not only a bounce, but it will also be calculated as 00:00:00 for the session duration. 

So you can see how this is a tricky metric, and why it should be taken with a grain of salt. Google Analytics cannot accurately track the total length of time a user spends on your website. 


Why does this matter?

Being able to accurately track how long users spend on your website helps you to understand exactly how engaging your content is, and what type of content is the most beneficial to driving qualified traffic. 

You also have to remember that the session duration metric shouldn’t be viewed on it’s own. It is directly related to other key metrics; bounce rate and avg. pages per session. If you have a low session duration, your bounce rate will likely be high, and your pages per session will be low. All of these are signs that you may need to make some improvements to your website. 

Another reason why this matters is RankBrain. If you’re not familiar with RankBrain, it’s an algorithm update that Google released in 2015. RankBrain uses machine learning to filter the search results to provide users the best answer to their queries. A few things that RankBrain looks at to help measure user satisfaction is session duration and bounce rate. If RankBrain doesn’t feel users are happy with the results shown, they will drop them.


Why do I have a low session duration?

This can be hard to answer given the nature of the metric. The main thing to consider is that maybe your content isn’t relevant or that users are just not connecting with it. Examine individual pages to see which ones are failing, and how they compare to ones with high session durations. 

You might also suffer from poor website design, which in turn is creating a negative user experience. If a user cannot find the information they are looking for, they will quickly leave and move on. Make sure your navigation is user-friendly and easy to understand. 

You will also want to ensure that your website loads quickly. If your website takes as long as 6 seconds to load, you can experience bounce rates as high as 46%. 

Of course having a low session duration doesn’t always have to be a negative thing. If you are providing users with highly relevant content, and they are able to find the information they need on the first page they land on, then you don’t really need to worry. It just depends on the goal you are trying to achieve with your website.


How can I improve my session duration?

You’ll want to consider what type of things you can incorporate into your website to help keep users more engaged. A few things to examine are:

  • Videos: By having a video on the page, you are not only encouraging a user to spend longer on that page, but you are also requiring them to take action (playing the video) which will result in Google Analytics being able to better track the time spent there. 
  • Add Images: No one wants to read large blocks of text. It can make a user feel overwhelmed. You can easily break up large chunks of text with some engaging images. 
  • Proper Formatting: Another easy way to break up blocks of texts. Add subheadings and break up large paragraphs into smaller ones.
  • Add Links to Other Pages: Another way to create more engagement on the site is to leverage internal linking. Make sure the link is relevant to the topic to better encourage a user to click.
  • Publish Quality Content: This is a bit of a no brainer. Many SEOs know that content is king, and oftentimes content gets pushed out and published just for the sake of having more content. This can easily result in high bounce rates and low session durations. You will want to actually consider what type of content your audience is looking for, and then find new and creative ways to write about topics they are interested in.


The best thing to remember is that you shouldn’t over analyze your average session duration. There are many factors at play. The main thing to consider is the overall nature of your website and the actions that you want your users to take. Having a firm understanding of how session duration is calculated, and the role it plays with other key metrics, is going to help you build a strong strategy to increase user engagement and get your stats to where you want them.