This article is about cookies usage for Google Analytics 4 properties. To learn about cookies for Universal Analytics, see this article instead.
The gtag.js JavaScript library uses first-party cookies to distinguish unique users as well as unique sessions from a single user. The library does not require you to set cookies to transmit data to Google Analytics.
gtag.js cookies
The following table describes each cookie set by gtag.js. To learn more about the data that Analytics collects, see Safeguarding your data.
| Cookie name | Default expiration time | Description |
|---|---|---|
| _ga | 2 years | Used to distinguish users. |
| _gid | 24 hours | Used to distinguish users. |
| _ga_<container-id> | 2 years | Used to persist session state. |
| _gac_gb_<container-id> | 90 days | Contains campaign related information. If you have linked your Google Analytics and Google Ads accounts, Google Ads website conversion tags will read this cookie unless you opt-out. Learn more. |
Change default cookie settings
You need the Editor role to use this feature. To override default cookie expiration and cookie update settings:
- In Admin, make sure that you have the desired account and property selected.
- In the Property column, click Data Streams > Web.
- Click the data stream for your website, then under Additional Settings, click More tagging settings.
- Click Override cookie settings.
- Select the Override default cookie settings checkbox.
- Under Cookie expiration select how long before cookies expire (from immediately to 25 months).
- Under Cookie update select either Set cookie expiration relative to most recent visit or Set cookie expiration relative to first visit.
- Click Save.
If you need to customize additional cookie settings, see Cookies and user identification.
Cookie settings configured using the global site tag or Google Tag Manager override settings configured in the Analytics interface.