If you have a website, you’ve probably heard someone say you need Google Analytics. Maybe you already have it installed and never look at it. Maybe you have no idea whether it’s set up at all.
Google Analytics 4 — GA4 — is the current version of Google’s free website analytics platform. It tells you who visits your website, what they do there, and whether your marketing is working. And as of July 2024, it’s the only version of Google Analytics available. The old version (Universal Analytics) is gone.
Here’s what you need to know.
What GA4 Actually Does
At its core, GA4 answers three questions:
- Who is coming to your website? Where they’re located, what device they use, how they found you.
- What are they doing? Which pages they view, what they click, whether they buy.
- Is your marketing working? Which channels drive traffic, which campaigns drive revenue, where people drop off.
It tracks this by placing a small piece of JavaScript code on every page of your website. When someone visits, the code sends data back to Google’s servers, and you see the results in your GA4 dashboard.
How GA4 Is Different From Universal Analytics
If you used the old Google Analytics (Universal Analytics, or “UA”), GA4 feels like a completely different product. That’s because it is.
| Feature | Universal Analytics (Old) | GA4 (Current) |
|---|---|---|
| Data model | Pageviews and sessions | Events (everything is an event) |
| Sessions | Defined by 30-min timeout | Defined by 30-min timeout, but de-emphasized |
| Bounce rate | % of single-page sessions | Replaced by engagement rate |
| Ecommerce | Enhanced Ecommerce plugin | Built-in ecommerce events |
| Cross-device | Limited | User-ID + Google Signals for cross-device |
| Machine learning | Basic | Predictive audiences, anomaly detection |
| Data retention | Unlimited | 2 or 14 months (configurable) |
| Cost | Free | Free (GA4 360 for enterprise) |
The biggest shift: everything is an event in GA4. A pageview is an event. A click is an event. A purchase is an event. A scroll is an event. In Universal Analytics, pageviews, events, and transactions were separate concepts. In GA4, they’re all events with different parameters.
For a detailed comparison, see our guide on GA4 vs Universal Analytics differences.
The Key Concepts You Need to Know
Events
Events are the building blocks of GA4. Every interaction is tracked as an event with a name and optional parameters.
GA4 has four types of events:
| Type | Examples | Who Creates Them |
|---|---|---|
| Automatically collected | page_view, first_visit, session_start | GA4 (built-in) |
| Enhanced measurement | scroll, click (outbound), file_download, video_start | GA4 (toggle on in settings) |
| Recommended | purchase, add_to_cart, sign_up, login | You (following Google’s naming conventions) |
| Custom | subscription_upgrade, feature_used | You (any name you want) |
The automatically collected and enhanced measurement events work out of the box. The recommended and custom events require setup — either through Google Tag Manager or directly in your website code.
Check our GA4 events reference for the complete list of recommended events and their parameters.
Users, Sessions, and Engagement
Users are individual people (identified by cookies, User-ID, or Google Signals). GA4 tracks “active users” — people who had an engaged session or triggered certain events.
Sessions start when someone arrives at your site and end after 30 minutes of inactivity. One user can have multiple sessions.
Engagement rate replaced bounce rate. A session is “engaged” if it lasted more than 10 seconds, had 2+ pageviews, or triggered a conversion event. Engagement rate is the percentage of sessions that were engaged.
This is a much more useful metric than the old bounce rate. A user who reads your entire blog post for 3 minutes and then leaves would have been a “bounce” in Universal Analytics. In GA4, that’s an engaged session.
For more on this shift, read our breakdown of bounce rate vs engagement rate in GA4.
Conversions (Key Events)
A conversion is any event you mark as important. In GA4, you simply toggle any event as a “key event” (Google recently renamed conversions to key events in the GA4 interface, though the concept is identical).
Common conversions:
purchase— Someone bought somethinggenerate_lead— Someone submitted a lead formsign_up— Someone created an account
You can mark up to 30 events as key events. These are the events that show up in your conversion reports and can be imported into Google Ads for campaign optimization.
Audiences
GA4 lets you create audiences — groups of users based on their behavior. For example:
- People who visited your pricing page but didn’t purchase
- Users who added to cart in the last 7 days
- Customers who’ve spent more than $500
These audiences can be shared with Google Ads for remarketing campaigns, making your ad targeting much more precise.
Explorations
Beyond the standard reports, GA4 has an “Explore” section where you can build custom analyses:
- Funnel exploration — See where users drop off in a multi-step process
- Path exploration — See the sequence of pages users visit
- Segment overlap — See how different user groups overlap
- Cohort analysis — Track how groups of users behave over time
This is where GA4 becomes genuinely powerful, but it requires time to learn. The standard reports cover most needs.
What GA4 Does Not Do
GA4 is not perfect, and it helps to understand its limitations:
It doesn’t track everything by default. Pageviews and basic interactions are automatic. Ecommerce events (purchases, add-to-cart) require setup. Form submissions usually need custom configuration.
It doesn’t store data forever. GA4 retains user-level data for either 2 months or 14 months (your choice in settings). After that, only aggregated data remains. Set this to 14 months immediately — our data retention settings guide shows you how.
It’s not real-time (mostly). There’s a real-time report, but standard reports have a 24-48 hour delay. If you made a change today and want to see the impact, wait until tomorrow.
It samples data on free accounts. If you’re analyzing large date ranges or complex segments, GA4 may sample your data (use a subset and extrapolate). This is usually fine for small-to-medium businesses but matters at scale.
It’s not a source of truth for revenue. GA4’s revenue numbers will never match your Shopify dashboard, your bank account, or your ad platform’s numbers. Use your e-commerce platform for actual revenue and GA4 for understanding user behavior and channel performance.
How to Check if GA4 Is Installed on Your Site
Method 1: Google Tag Assistant
- Install the Google Tag Assistant Chrome extension
- Visit your website
- Click the extension icon
- If GA4 is installed, you’ll see a tag with an ID starting with “G-”
Method 2: View Page Source
- Right-click on your website and select “View Page Source”
- Search for
gtagorG-orgoogletagmanager - If you find a script containing a
G-XXXXXXXID, GA4 is installed
Method 3: GA4 Real-Time Report
- Log into analytics.google.com
- Go to Reports, then Realtime
- Open your website in another tab
- If you see your visit appear in real-time, GA4 is working
If GA4 is installed but you’re not seeing data, our troubleshooting guide for missing GA4 data covers the most common causes.
How to Set Up GA4
If you don’t have GA4 yet:
- Go to analytics.google.com and create an account
- Create a property (one property per website)
- Get your Measurement ID (starts with
G-) - Add the GA4 tag to your website via Google Tag Manager or by pasting the code directly
For Shopify: GA4 is built into Shopify’s Online Store settings. Go to Online Store, then Preferences, scroll to Google Analytics, and enter your GA4 Measurement ID.
For WordPress: Use a plugin like Site Kit by Google or add GTM manually.
For custom sites: Install via Google Tag Manager or add the gtag.js snippet directly to your site’s <head>.
What to Do After Installation
GA4 collects basic data automatically, but there’s a checklist of things to configure:
- Set data retention to 14 months (Admin, Data Settings, Data Retention)
- Enable Enhanced Measurement (Admin, Data Streams, toggle on scroll, outbound click, file download, video engagement, site search)
- Exclude internal traffic — Filter out your own visits so they don’t pollute your data. See our internal traffic exclusion guide.
- Mark key events — Toggle your important events (purchase, lead form submission) as key events
- Link to Google Ads — If you run Google Ads, link the accounts so conversion data flows between them
- Set up ecommerce tracking — If you sell products, configure the ecommerce events (view_item, add_to_cart, purchase)
The Bottom Line
GA4 is the free analytics platform every website needs. It tells you who’s visiting, what they’re doing, and whether your marketing is working. The interface takes some getting used to, and ecommerce tracking requires setup, but the data it provides is essential for making informed marketing decisions.
If you’re not sure whether GA4 is set up correctly on your site — or whether it’s capturing the data you actually need — run a free scan. We’ll check your analytics setup in about 60 seconds and tell you exactly what’s working and what’s missing.