A Google Analytics 4 session is counted every time someone visits your site or app. This is how sessions are initiated:
- App: A user opens your app on their phone in the foreground
- Website: A user views a page on your website
Let’s take a look at how the GA4 session timer stops and starts, how you can change it, and the difference between a regular session and an engaged session.
- How are GA4 sessions counted?
- ga_session_id Parameter
- ga_session_number Parameter
- When does the Google Analytics 4 session timer reset?
- How To Change Google Analytics 4 Session Timeout Limit
- Change in App Stream
- Change in Web Stream
- What is an engaged session in GA4?
- Bounce Rate vs. Engaged Sessions in GA4
- How do you calculate bounce rate in Google Analytics 4?
How are GA4 sessions counted?
(In order to access these this information in your Explore reports, you must create a custom dimension for each one.)
A session ID, identified by the ga_session_id parameter, is generated each time a user comes to your site. If the same user comes to your site, leaves, and comes back to initiate a new session, two different session IDs are generated.
The same user can have multiple session IDs, because each new session generates a new ID, regardless of the user.
The session number, identified by the ga_session_number parameter, counts the different number of sessions generated by each user.
Here’s a simplified example of how the session_start event and its ga_session_id and ga_session_number parameters are structured:
When does the Google Analytics 4 session timer reset?
Google’s default timer ends sessions after 30 minutes of inactivity.
Let’s say someone opens your app on their phone so that it is in the foreground. That person has initiated a session. (This example applies to visitors to your website, too.)
They spend one minute on your app (or website) before checking their email, opening a social media app, sending a WhatsApp message, and setting their phone down to charge.
An hour later, they pick up their phone and access your app (or website) again. Is this considered a new session in Google Analytics 4?
Yes, even though your app (or app) was running in the background. After 30 minutes of your app (website) not being in the foreground, the user’s initial session ended.
But just because there’s a 30-minute inactivity limit before a new session is initiated, it does not mean that the user’s initial session was 31 minutes.
Since the user was inactive for 30 minutes, their active session timer will have been paused at the beginning of those 30 minutes.
How To Change Google Analytics 4 Session Timeout Limit
If you prefer a different timeout limit than 30 minutes, here’s how to change it:
Change in App Stream
Use the setSessionTimeoutDuration method and specify your desired limit down to the millisecond*
*In fact, the default is not actually 30 minutes, but rather 1,800,000 milliseconds, which is equal to 30 minutes.
Change in Web Stream
- Go to Admin
- Click Data Streams
- Click your web data stream
- Scroll down and click More Tagging Settings, which is the last option under Additional Settings
- Click Adjust session timeout
- Choose how long your want your session timeouts to last in minutes and hours
(You can also change your timer limit for engaged sessions)
What is an engaged session in GA4?
- The session must last at least 10 seconds (or 10,000 milliseconds) AND/OR
- One or more conversion event was completed AND/OR
- The user viewed two or more screens (app) or pages (web)
You can change the minimum session duration to activate an engaged session. Follow the steps in the previous section to do so.
Bounce Rate vs. Engaged Sessions in GA4
In GA4, bounce rate is not calculated the same way as it was in UA. Bounce rate and engagement rate are now inversions of each other.
In most cases, your goal should be to have a low bounce rate and a high percentage of engaged sessions.
How do you calculate bounce rate in Google Analytics 4?
Google Analytics 4 bounce rate was added July 11, 2022. It’s the inverse of engagement rate.
That means your bounce rate in GA4 is 100 minus your engaged sessions percentage.
e.g. If your engaged sessions percentage is 50%: 100 – 50 = 50% bounce rate.
Non-engaged sessions are any GA4 sessions that last less than 10 seconds and don’t include a conversion event nor multiple pages/screens.