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How are sessions counted in GA4?
Sessions = visits that began in the period (one session_start each)
GA4 gives each visit a session ID. A visit that runs past midnight stays one session, and so does a visit whose traffic source changes halfway.
Source: Analytics Help, About Analytics sessions.
The timeout is a setting of your web stream. The default is 30 minutes of inactivity. You can raise it to 7 hours 55 minutes, which merges more activity into fewer sessions.
Google Analytics totals a period itself. Daily figures do not add up to it exactly, because a late-night visit can show on two dates.
One site, every source
Sessions covers the whole property: organic search, email, direct visits, social and ads together. It tells you how busy the site was, not what the ads brought.
Ad clicks and the sessions they open never match one for one. Sessions from Google Ads explains that gap and how to watch it.
Worked example
A tea shop records 18,400 sessions in March. Its Google Ads account shows 6,100 clicks for the same month. That does not mean ads brought a third of the visits. The 18,400 include organic search, email, direct visits and social.
The fair comparison is Visits from ads, which Google Analytics puts at 5,300 for March. Ads brought 29% of the site's sessions, and 5,300 of 6,100 clicks became a recorded visit.
Where do you find sessions in GA4?
- In Google Analytics, open Reports, then Acquisition, then Traffic acquisition. Sessions is a column, split by session source and medium.
- The total row at the top of that table is the site's sessions for the dates chosen.
- In Explore, add the Sessions metric to a free-form exploration to split it by page, device or country.
- To change the timeout, open Admin, Data streams, your web stream, Configure tag settings, then Adjust session timeout.
How does Optizads read sessions?
Sessions sits under Site traffic in Add a metric, once Google Analytics is connected and one property chosen. It can go on an Overview card, in a report's Key figures or Performance chart, or become a goal.
Optizads never adds daily sessions up itself. For any period it asks Google Analytics for its own total over the exact days, keeps that answer 30 minutes, and shows it. If Analytics cannot be read at that moment, the card stays empty rather than showing a sum of days that would be wrong.
The whole site
Sessions belong to the property, not to a campaign. When you narrow the figures to one campaign type, Google Analytics figures are left out.
What are the common mistakes with sessions?
- Reading total sessions as ad traffic. They come from every source.
- Adding daily sessions from an export to get the month. A visit past midnight can be counted on both days.
- Joining GA4 sessions to Universal Analytics sessions from before July 2023. Universal Analytics restarted a session at midnight and on a source change, so the two series do not match.
- Changing the session timeout, then comparing the months before and after as if nothing changed.
Related terms
- Google tag: The piece of code on your website that sends conversions and site data to Google Ads and Google Analytics.
- UTM parameters: Tags added to a link, such as utm_source and utm_campaign, so analytics tools know where a visit came from.
- GCLID: The Google click identifier added to a landing page address when someone clicks an ad.
Related metrics
- Sessions from Google Ads (GA4): Sessions from Google Ads are the GA4 sessions whose source and medium are google / cpc, which is how auto-tagged Google Ads clicks arrive.
- Engaged sessions (GA4): An engaged session in Google Analytics 4 is a visit that lasted longer than 10 seconds, viewed at least two pages or screens, or triggered a key event.
- Active users (GA4): Active users in Google Analytics 4 are the distinct people who had an engaged session on your site or app, or visited it for the first time, in the period.
- Engagement rate (GA4): Engagement rate in Google Analytics 4 is the share of sessions that were engaged: engaged sessions divided by sessions.
