An ad session is a period of interaction with your site from a unique visitor on a particular device.
You can think of the ad sessions metrics as a way of bundling up the ads-related actions that a user takes on your website. For example, a single ad session can contain multiple page views and ad impressions.
AdSense uses cookies to associate an ad session with a unique user and device. In some cases, it’s not possible to associate an ad request with an ad session, such as, if a user or user’s browser setting has disabled or deleted cookies, or they’ve opted out of personalised ads.
How long does an ad session last?
By default, an ad session ends after either 30 minutes of inactivity or at midnight United States Pacific Time (PST):
- 30 minutes of inactivity
AdSense starts counting from the moment a user arrives on your site. If 30 minutes pass without any kind of interaction with the ads on your site from that user, the ad session ends. However, every time the user interacts with your site (for example, opens a new page with ads), AdSense resets the expiry time by adding 30 minutes from the time of that interaction.
- Midnight
If a user arrives on your site at 11.50 p.m. on 14 August and leaves at 12.10 a.m. on 15 August. AdSense records two ad sessions: one ending at 11:59:59 p.m. on 14 August, and one beginning at 12.00 a.m. on 15 August.
As soon as one ad session has ended, the user can start a new ad session. The user can interact with your website during multiple ad sessions occurring on the same day or over several days, weeks or months.
Differences between sessions in AdSense and Google Analytics
The main difference between ad sessions in AdSense and those in Google Analytics is the way they're measured.
AdSense only measures sessions on pages containing ads, whereas Google Analytics measures sessions on all pages, whether or not they have ads. If a visitor to your site doesn't view any ads during their visit (for example, because they're using an ad blocker), AdSense won't record a session, but Google Analytics will record one.
Additionally, you might find differences between sessions in AdSense and Google Analytics in these cases:
- Your pages with AdSense ads might not also have the Google Analytics tracking code on them, and vice versa.
- AdSense might not be able to measure 100% of the ad sessions on your website, for example, if a user has changed their cookie settings or installed an ad blocker.
- Google Analytics opens a new ad session every time that a user's campaign source changes.
- Google Analytics allows you to change the ad session timeout so that ad sessions end after a specified amount of time rather than the default 30 minutes of inactivity.
- Google Analytics might use midnight in a different timezone than AdSense to end ad sessions.
- AdSense session metrics show how users interact with the ads on your website, whereas Google Analytics shows interactions with your pages. So multiple ad impressions in AdSense might correspond to a single 'impression' in Google Analytics.
