Data and measurement

What is GA4 (Google Analytics 4)

Also known as: Google Analytics 4, Google Analytics

Rodrigo Fávaro Founder of ROO3

Published October 30, 2026

Short answer

GA4, or Google Analytics 4, is the current version of Google Analytics, Google's free tool for measuring what happens on a website or app. It records everything as events instead of sessions, brings website and app data into the same property and includes privacy and modeling features. It replaced Universal Analytics, which stopped processing data on July 1, 2023.

Hypothetical example

An online store installs GA4 and marks purchases, chat button clicks and wholesale form submissions as key events. It links the property to its Google Ads account.

At the end of the month, the report shows which channels drove each key event. The store finds that organic search brings few direct sales but many wholesale inquiries, and starts measuring organic by the right outcome.

What changed from Universal Analytics

Universal Analytics stopped processing data on July 1, 2023, and, starting the week of July 1, 2024, its historical data was no longer accessible.

The main differences
	Universal Analytics	GA4
Data model	Session based	Event based
Website and app	Separate properties	Same property
Bounce	Single page session	Non engaged session
Privacy	Cookie dependent	Cookieless measurement and behavioral and key event modeling

Events and key events

In GA4, every interaction is an event: page view, scroll, click, form submission, purchase. The events that represent what matters to the business are marked as key events, and GA4 uses them to measure results and credit channels.

Marking an event as key applies from the moment it is marked and does not change past data. Google notes it can take up to 24 hours for the event to show as a key event in standard reports.

First steps

Create the property and install the Google tag across the site, directly or through Tag Manager.
Define key events: purchase, lead, contact, signup.
Link GA4 to Google Ads and Search Console.
Set up the cookie banner and consent mode.
Use UTM parameters on campaign links outside Google.
Review acquisition and attribution reports at least weekly.

Where GA4 tends to confuse

Numbers do not match the ad platform's, because each measures by its own rules.
Traffic with no source appears when campaign parameters are missing.
A key event firing too often inflates results.
Data from users who declined cookies appears partially or modeled.

Frequently asked questions

What is GA4?

Google Analytics 4, the current version of Google Analytics. It measures websites and apps with an event based model and includes privacy and predictive features.

Does Universal Analytics still work?

No. It stopped processing data on July 1, 2023, and its historical data was no longer accessible starting the week of July 1, 2024.

What is a key event in GA4?

An event marked as important to the business, such as a purchase or form submission. GA4 uses these events to measure results and credit channels.

Is GA4 free?

Yes, the standard version is free. There is a paid version, Google Analytics 360, for companies with larger needs.

Why does GA4 show different numbers than Google Ads?

Because the two tools count conversions with different attribution, window and deduplication rules. Comparing trends is more useful than demanding the same number.

Related terms

Sources

Rodrigo Fávaro

Founder of ROO3, a marketing and technology agency in São José do Rio Preto, Brazil. Builds AI products running in production (Tobia, gerar.app, Pense Mercado) and maintains the AI Benchmark, a public ranking of AI models.

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