_ga_<container-id> Cookie: What It Is, Who Sets It, and Consent Rules

What the _ga_<container-id> Cookie Does on Your Site

The _ga_<container-id> cookie is a first-party analytics cookie that Google Analytics 4 sets to keep the session state of a single property. The _ga_<container-id> cookie stores the start time of the current session, the number of sessions, and the time of the last hit. Google describes the _ga_<container-id> cookie as "Used to persist session state". The <container-id> part is the measurement ID of the property without the G- prefix, so the measurement ID G-CSJ3Z71FRB writes a cookie named _ga_CSJ3Z71FRB.

The value of the _ga_<container-id> cookie looks like GS2.1.s1712345678$o3$g1$t1712349999$j55$l0$h0. The table explains each part. Google publishes no value format. Read the meanings in the table as an interpretation that Google has not confirmed.

Who Sets the _ga_<container-id> Cookie

Google Analytics 4 sets the _ga_<container-id> cookie through the same Google tag (gtag.js) that writes the _ga cookie, added to the page directly or through Google Tag Manager. Each Google Analytics 4 property on the page writes its own cookie, named after its measurement ID. A site that sends data to 2 properties carries 2 _ga_<container-id> cookies next to a single _ga cookie.

The Google tag writes the cookie with JavaScript on your own domain, which makes the cookie a first-party cookie. Google describes the purpose as keeping the session state, so Google Analytics 4 knows whether a page view belongs to a running session or starts a new session.

Read how Google LLC handles the data in the Google Analytics 4 privacy policy, and sign the Google Ads Data Processing Terms, which cover Google Analytics before you collect data from visitors in the EU or the UK. Both documents appear in the sources at the end of this page.

Does the _ga_<container-id> Cookie Need Consent?

Yes, the _ga_<container-id> cookie needs consent in the EU, needs consent in the UK unless the statistics exception covers your setup, and needs no prior opt-in in California. The table gives the rule for each law.

The consent table describes what each law requires and is not legal advice. Whether a law applies to your site depends on where your visitors are, where your business is based, and how you set up Google Analytics 4, such as Google signals and the data sharing settings of the account.

The ePrivacy Directive requires consent before a site sets the _ga_<container-id> cookie. The General Data Protection Regulation (GDPR) sets the standard for that consent: freely given, specific, informed, and unambiguous.

The UK Privacy and Electronic Communications Regulations (PECR) exempt analytics cookies that produce aggregate statistics to improve the site. The exemption comes from the Data (Use and Access) Act 2025 and took effect on 5 February 2026. The exemption needs clear information for visitors and a simple and free way to object, according to the ICO guidance on the exceptions. The exemption allows no tracking or profiling of individual visitors. The vendor needs to act as your processor, and recordings of individual visitors and advertising purposes stay outside the exemption. The exemption covers the _ga_<container-id> cookie only while Google acts as your processor. Turn off Google signals and the data sharing settings of the account before you rely on the exemption, and check your setup against the ICO guidance.

The California Consumer Privacy Act (CCPA) sets no general opt-in requirement before a site sets the _ga_<container-id> cookie. Visitors get no right to opt out of the _ga_<container-id> cookie while Google Analytics 4 acts as your service provider. The service provider role needs a contract that limits the use of the data to the service for your site.

Read how each law decides which cookies need consent in the EU ePrivacy Directive + GDPR guide, the UK PECR guide, and the California CCPA guide.

How to Block the _ga_<container-id> Cookie Until Visitors Accept

Block the _ga_<container-id> cookie by holding back the Google tag (gtag.js) until the visitor accepts analytics cookies. TermsFeed Free Cookie Consent and TermsFeed Privacy Consent place Google Analytics 4 in the analytics category. Check whether an exemption applies to your own use of Google Analytics 4 in the consent rules for the _ga_<container-id> cookie.

<script type="text/plain" data-cookie-consent="tracking" async src="https://www.googletagmanager.com/gtag/js?id=TAG_ID"></script>
<script type="text/plain" data-cookie-consent="tracking">
  window.dataLayer = window.dataLayer || [];
  function gtag(){dataLayer.push(arguments);}
  gtag('js', new Date());
  gtag('config', 'TAG_ID');
</script>

Block the _ga_<container-id> Cookie With Google Consent Mode v2

Google Consent Mode v2 loads the Google tag before consent and stops the Google Analytics 4 cookies while analytics_storage is denied. Google tags "won't read or write first-party analytics cookies" while analytics_storage is denied, according to the Google consent mode documentation.

Advanced consent mode sends measurements without cookies to Google while consent is denied, and Google uses them for modeling. Basic consent mode loads no Google tag before the visitor answers. Choose basic consent mode to send no request to Google before consent.

Set up the default and the update calls with how to integrate Google Consent Mode v2 with Cookie Consent.

How to Verify That the _ga_<container-id> Cookie Waits for Consent

Verify the setup in a private window. Open Chrome DevTools, select the Application tab, and open Cookies. Click "I decline" on the consent banner and reload the page. The _ga_<container-id> cookie must not appear in the list until you accept analytics cookies.

How Long the _ga_<container-id> Cookie Lasts

The _ga_<container-id> cookie lasts 2 years (730 days), and the lifetime restarts at every page view. Chrome keeps the cookie for 400 days (about 13 months) at most, according to the Chrome team. Safari caps the cookies that JavaScript sets at 7 days of Safari use without an interaction with your site, according to the WebKit team behind Safari.

The session inside the cookie ends long before the cookie expires. A session times out after 30 minutes without activity by default, and the next page view starts a new session in the same cookie, according to Google. Change the session timeout in Google Analytics under Admin, Data streams, Configure tag settings, and Adjust session timeout.

The Override cookie settings in the Google Analytics interface and the cookie_expires setting of the Google tag change the lifetime of the Google Analytics cookies. The _ga and _ga_<container-id> cookies therefore keep the same lifetime.

Cookies That Work Together With _ga_<container-id>

Google Analytics 4 sets 1 other cookie next to the _ga_<container-id> cookie in its current setup, and older versions set 4 more. Rows marked "older version" come from earlier versions of Google Analytics 4 that still run on some sites.

Scripts and Requests of Google Analytics 4 That Come With the _ga_<container-id> Cookie

The catalog lists 6 scripts, pixels, and data endpoints of Google Analytics 4, which a cookie scanner or the Network tab of Chrome DevTools shows next to the _ga_<container-id> cookie. Block the main script, and the requests in the table stop with the main script.

_ga_<container-id> Cookie FAQs

Why does my site have 2 _ga_ cookies?

Your site sends data to 2 Google Analytics 4 properties, and each property writes its own _ga_<container-id> cookie. Compare the part after _ga_ with the measurement IDs in Google Analytics, under Admin and Data streams, to find both properties. Remove the tag of the property you no longer use, and the extra cookie stops at the next visit.

Is the _ga_ cookie necessary?

No, the _ga_<container-id> cookie is not a strictly necessary cookie. Firstly, the cookie serves the analytics reports of your site, not a service the visitor asks for. Secondly, your site works the same for a visitor who refuses analytics cookies. Thirdly, Google tags read and write no first-party analytics cookies while analytics_storage is denied in Google Consent Mode v2, according to Google.

How do I rename the _ga_ cookie?

Add a cookie_prefix value to the configuration of the Google tag, and the Google tag adds the prefix to the names of the Google Analytics cookies. A cookie scanner then reports the cookies under the new names. Update your Cookies Policy with the new names, so the list matches what visitors find in the browser.