Understanding Google Analytics 4 (GA4): Complete Guide
Set up and use Google Analytics 4 to track website traffic, user behaviour, and conversions. Key reports explained.
Why Google Analytics 4?
GA4 replaced Universal Analytics (UA) in July 2023. All new Google Analytics properties are GA4. If you are starting from scratch in 2026, you use GA4.
GA4 has a fundamentally different data model from UA. Understanding the new model is essential for meaningful analysis.
The GA4 Data Model: Events, Not Sessions
Universal Analytics was built around sessions and pageviews. GA4 is built around events.
In GA4, everything is an event: page views, button clicks, video plays, form submissions, scrolls, file downloads. Each event can have parameters that add detail.
Standard automatic events: page_view, first_visit, session_start, scroll (when user scrolls 90%), click (outbound links), file_download, video_start, video_progress, video_complete.
Setting Up GA4
For WordPress: Use the "Site Kit by Google" plugin — connects GA4 in one click without code.
Manual installation: Add the gtag.js snippet to your website header, or use Google Tag Manager.
Key GA4 Reports
Realtime: Who is on your site right now. Useful for monitoring live campaigns.
Life cycle reports: Acquisition (where traffic comes from), Engagement (what users do on site), Monetisation, Retention.
User reports: Demographics, technology.
Important GA4 Metrics
Users vs New Users: Total unique visitors vs those visiting for the first time.
Sessions: Individual visit periods. One user can have multiple sessions.
Engaged sessions: Sessions lasting 10+ seconds, with a conversion, or with 2+ pageviews. GA4's replacement for "non-bounce sessions."
Engagement rate: % of sessions that are engaged. Replaces bounce rate (engagement rate = 1 minus bounce rate roughly).
GA4 vs Universal Analytics: Key Differences
| Feature | GA4 | Universal Analytics |
|---|---|---|
| Data model | Events | Hits (pageviews, sessions) |
| Bounce rate | Engagement rate instead | Bounce rate |
| Cross-device tracking | Built-in | Limited |
| Data retention | 14 months max (free) | Unlimited (historical) |
| Machine learning | Predictive metrics | Limited |
Adding Google Analytics to Lazyblink
Once you have your GA4 Measurement ID (G-XXXXXXXXXX), add it to your Next.js app in the layout.tsx file inside a Script tag. Track page views, tool usage, and user engagement across all 146+ tools.
Frequently asked questions
Is Google Analytics 4 free?
Yes — Google Analytics 4 is completely free. There is a paid enterprise version (Google Analytics 360) for very large organisations, but GA4 is sufficient for most websites.
What is the difference between GA4 and Universal Analytics?
GA4 uses an event-based data model vs UA's session-based model. GA4 includes cross-device tracking, machine learning insights, and is privacy-focused for a cookieless future. UA was sunset in July 2023.