What Is GA4 (Google Analytics 4)?

GA4 is the current version of Google Analytics, and if you used Google Analytics before, it works differently from what you are used to. This guide explains what GA4 is in plain English: what it does, how it differs from the old Universal Analytics, the key concepts behind it, and how to start using it well.

What is GA4?

GA4, short for Google Analytics 4, is Google's free analytics platform for measuring traffic and engagement across your website and apps. It is the successor to Universal Analytics, which Google shut down in July 2023, so GA4 is now the only version of Google Analytics that collects new data.

The headline difference is that GA4 is built around events rather than pageviews and sessions. Every interaction, a page view, a click, a scroll, a purchase, is collected as an event. That makes GA4 more flexible than Universal Analytics, but it also means the reports and the setup look and behave differently.

How GA4 differs from Universal Analytics

If you are asking what GA4 is, you are probably also wondering how it compares to the Universal Analytics most people grew up with. The main differences:

• Event-based, not session-based. Universal Analytics organised data around sessions and pageviews. GA4 treats everything as an event with parameters, which is more flexible but less familiar.
• One property for web and app. A single GA4 property can measure a website and a mobile app using separate data streams.
• Engagement over bounce rate. GA4 replaces bounce rate with engagement metrics like engaged sessions and engagement rate.
• Conversions are now key events. What Universal Analytics called goals are now called key events in GA4.
• Privacy and modelling built in. GA4 is designed for a world with more consent restrictions, with features like Consent Mode and modelled data.

The practical takeaway: you cannot simply copy a Universal Analytics setup into GA4. It needs to be planned around the event model, which is why a clean GA4 implementation matters.

The event-based data model

Everything in GA4 is an event. An event has a name (like page_view or purchase) and parameters that describe it (like page_location or value). GA4 collects some events automatically, and you can add your own custom events for the actions that matter to your business.

This model is powerful because you decide what to measure. It is also why GA4 setups go wrong: if events are named inconsistently or fire more than once, the data becomes unreliable. Getting the event structure right is the single most important part of using GA4 well.

Key GA4 concepts

A few terms come up constantly once you start using GA4:

• Property: the container for your data. Most businesses have one GA4 property per brand.
• Data stream: the source of data within a property, for example a website or an app.
• Event: any interaction GA4 collects, with parameters that add detail.
• Key event: an event you have marked as important, such as a purchase or a lead. This is GA4's version of a conversion.
• Engagement rate: the share of sessions that were engaged, which GA4 uses instead of bounce rate.
• Dimensions and metrics: dimensions are what you group by (like country), metrics are the numbers (like sessions).

There is more in our GA4 glossary if you want the full vocabulary.

What GA4 is good at, and its limits

GA4 is strong at flexible event tracking, cross-platform measurement, free integration with Google Ads and BigQuery, and privacy-aware modelling. It is weaker on out-of-the-box reporting: many people find the default reports harder to read than Universal Analytics, which is why teams pair GA4 with Google Data Studio for clearer dashboards.

Above all, GA4 is only as good as its setup. A clean implementation gives you trustworthy data; a rushed one gives you confident-looking numbers that are wrong.

How to get started with GA4

To start using GA4 well:

1. Create a GA4 property and a data stream for your site.
2. Install GA4, ideally through Google Tag Manager, rather than hard-coding tags.
3. Plan the events and key events that map to how your business converts.
4. Validate everything in DebugView before you trust the reports.

Our complete GA4 setup guide walks through each step in detail.

Get help with GA4

If you would rather have GA4 set up or fixed properly the first time, that is what we do. Start with a GA4 audit to see what is working, or explore our GA4 services for setup, implementation and reporting.