Explanation of Cookie Values Used by Google Analytics 4

Table of Contents

Update time: August 17, 2023

This article introduces the cookies generated in GA4, GA4 will generate two cookies to distinguish users and sessions:

Cookie name	Default expiration time	Description
_ga	2 years	Used to distinguish users.
_ga_<container-id>	2 years	Used to persist session state.

Note：Although the default validity period of these two cookies is 2 years, due to some browser restrictions on first-party cookies, the maximum validity period is 400 days, so in fact, the validity period is about 13 months.

Next, let me introduce the specific information in these two cookies, take bbccss.com as an example:

_ga

The detailed explanation is as follows:

Value	Description
GA1	Version number, which represents the version of the cookie format that’s being used.
1	Domain Level, In fact, GA4 generates all 1.
1197596843	Random Number, 10 digits
1673515099	Timestamp, the timestamp when cookie _ga was created

1197596843.1673515099 composed of 1197596843 and 1673515099 is what we usually call Client ID.

_ga_<container-id>

The detailed explanation is as follows:

Value	Description
GS1	Fixed String: Google Stream 1
1	Domain Level, In fact, GA4 generates all 1.
1673933110	Session ID/Current Session Start Time
12	Sessions Count
0	Engagement Session, 1 means engagement session, 0 means no
1673933110	Current Timestamp
60	Countdown，60-second countdown may be used to calculate the Engagement Session or the time spent on the page.
0	to be determined
0	to be determined

For the first request of the session, the Session ID and Current Timestamp are the same, because the Session ID is the Current Session Start Time

Referral：

Cross-Domain Tracking on Google Analytics 4 (GA4)

If you don't understand, You can leave a comment below.

_ga

_ga_<container-id>

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