Google Analytics 4 (GA4) represents a fundamental shift from Universal Analytics (UA), transitioning from session-based to event-based tracking. With Universal Analytics sunsetting in July 2023, understanding the differences and planning your migration is crucial for maintaining accurate website analytics.
🎯 Quick Comparison: GA4 vs Universal Analytics
| Feature | Google Analytics 4 (GA4) | Universal Analytics (UA) |
|---|---|---|
| Data Model | Event-based | Session and pageview-based |
| Cross-Platform Tracking | ✅ Web + App unified | ❌ Separate properties |
| Machine Learning | ✅ AI-powered insights | ⚠️ Limited |
| Privacy Features | ✅ Cookieless tracking options | ❌ Cookie-dependent |
| Data Retention | 2-14 months (default 2) | Indefinite (26-50 months) |
| Reporting Interface | Simplified, exploration-focused | Detailed pre-built reports |
| BigQuery Export | ✅ Free for all | ❌ Only GA360 (paid) |
| Future Support | ✅ Active development | ❌ Deprecated (July 2023) |
💡 What Changed from Universal Analytics to GA4?
1. Data Model: Sessions vs Events
Universal Analytics: Built around sessions and pageviews. A session is a group of user interactions within a 30-minute window.
GA4: Everything is an event. Page views, clicks, scrolls, video plays - all tracked as events with parameters. This provides more flexibility and granular data.
2. Cross-Platform Measurement
Universal Analytics: Required separate properties for web and mobile app tracking, making cross-platform analysis complex.
GA4: Single property can track users across website and mobile apps, providing unified customer journey insights.
3. Privacy and Cookie Handling
Universal Analytics: Heavily relies on cookies for user identification and tracking.
GA4: Designed for a privacy-first world with modeling capabilities to fill data gaps when cookies aren't available. Supports cookieless tracking and consent mode.
4. Reporting and Interface
Universal Analytics: Extensive pre-built reports covering every aspect of your data. Familiar but sometimes overwhelming interface.
GA4: Streamlined reports with emphasis on "Analysis Hub" for custom exploration. Fewer default reports but more powerful custom analysis.
5. Machine Learning and Predictive Metrics
Universal Analytics: Limited ML capabilities, primarily for anomaly detection in GA360.
GA4: Built-in AI predictions including purchase probability, churn probability, and revenue prediction. Automatic insights and anomaly detection for all users.
📊 Feature-by-Feature Comparison
Enhanced Measurement
UA: Manual event tracking setup required for most interactions beyond pageviews.
GA4: Automatic tracking for scrolls, outbound clicks, site search, video engagement, and file downloads with simple toggle switches.
Conversion Tracking
UA: Limited to 20 goals per view. Requires goal setup in admin panel.
GA4: Unlimited conversions. Any event can be marked as a conversion with one click.
User Identification
UA: Relies on Client ID (cookie-based) and optionally User ID for authenticated users.
GA4: Multiple identification methods including Google signals, User ID, device ID, and modeling for unidentified traffic.
Data Freshness
UA: 24-48 hour delay for full processing. Real-time reports show only active users.
GA4: Most reports update within 4 hours. Improved real-time reporting shows events and conversions immediately.
Custom Dimensions and Metrics
UA: Limited to 20 custom dimensions and 20 custom metrics per property (200 for GA360).
GA4: 50 custom dimensions (event-scoped), 25 custom dimensions (user-scoped), and 50 custom metrics per property.
Reporting API
UA: Multiple APIs (Core Reporting API, Real Time API, etc.).
GA4: Unified Data API with improved flexibility and query capabilities.
⚡ Key Advantages of GA4
- Future-Proof: Only actively developed Google Analytics platform
- Predictive Insights: AI-powered metrics predict user behavior
- Better Privacy Compliance: Built for GDPR, CCPA, and cookieless future
- Cross-Platform Tracking: Unified view of customer journey across web and app
- Enhanced Measurement: Automatic event tracking without code
- BigQuery Integration: Free raw data export for advanced analysis
- Flexible Event Model: More granular data collection and analysis
- Improved Attribution: Data-driven attribution model included
- Integration with Google Ads: Better remarketing and optimization
⚠️ Challenges with GA4
- Learning Curve: Completely different interface and concepts require retraining
- Fewer Standard Reports: Must build many reports manually in Exploration
- Different Metrics: Data doesn't match UA exactly (different methodology)
- Limited Historical Data: Can't import UA data; must run parallel during transition
- Shorter Data Retention: Default 2 months vs UA's 26+ months
- Missing Features: Some UA features haven't been replicated yet
- Complex Migration: Requires complete setup rebuild, not simple upgrade
🔍 Should You Switch to GA4?
Short Answer: Yes, you must. Universal Analytics stopped processing data on July 1, 2023. GA4 is not optional - it's the replacement.
Migration Timeline
- Now: If you haven't already, set up GA4 immediately
- Parallel Running: Run GA4 and UA in parallel to compare data and train your team
- Build GA4 Reports: Recreate your essential UA reports in GA4 Explorations
- Train Your Team: Ensure everyone understands the new interface and methodology
- Export UA Data: Export historical UA data before it's deleted (available for 6 months post-sunset)
- Full Transition: Make GA4 your primary analytics platform
🚀 GA4 Migration Checklist
Pre-Migration (Before Setup)
- ✅ Document your current UA setup (goals, events, custom dimensions)
- ✅ Export historical UA data and reports you need long-term
- ✅ Audit what UA features you actually use
- ✅ Identify stakeholders and reporting needs
GA4 Setup
- ✅ Create GA4 property (keep UA running in parallel)
- ✅ Install GA4 tracking code (gtag.js or Google Tag Manager)
- ✅ Enable Enhanced Measurement for automatic events
- ✅ Set up data streams for web and/or app
- ✅ Configure user properties and custom dimensions
- ✅ Set up custom events for business-critical actions
- ✅ Mark important events as conversions
- ✅ Link to Google Ads and Search Console
- ✅ Configure BigQuery export (optional but recommended)
- ✅ Set data retention to 14 months (max available)
Post-Migration
- ✅ Build custom reports and explorations
- ✅ Create dashboards for key stakeholders
- ✅ Set up audiences for remarketing
- ✅ Train team on new interface and methodology
- ✅ Monitor data quality and compare to UA baseline
- ✅ Adjust tracking as needed based on business needs
💰 Pricing Comparison
| Feature | GA4 Free | GA4 360 | UA Free | UA 360 |
|---|---|---|---|---|
| Price | Free | $50,000+/year | Free (deprecated) | $150,000+/year |
| Event Limit | 500 unique events | Unlimited | 20 goals | 200 goals |
| Data Retention | 2-14 months | 14-50 months | 26 months | 50 months |
| BigQuery Export | ✅ Free | ✅ Included | ❌ | ✅ Included |
| Support SLA | ❌ | ✅ | ❌ | ✅ |
| Data Sampling | ⚠️ At scale | Higher thresholds | ⚠️ At scale | Minimal |
❓ Frequently Asked Questions
Can I use both GA4 and Universal Analytics together?
Yes, and this was recommended during the transition period. However, Universal Analytics stopped collecting data on July 1, 2023. You should have already transitioned fully to GA4.
Will my historical Universal Analytics data transfer to GA4?
No. GA4 cannot import historical UA data due to different data models. You must export your UA data before it's deleted (6 months after sunset). Run both platforms in parallel to build GA4 historical data.
Why are my GA4 numbers different from Universal Analytics?
Different data models and measurement methodologies mean numbers won't match exactly. GA4 uses event-based tracking while UA used session-based. This is expected and normal.
Do I need to rewrite all my custom tracking code for GA4?
Partially. While basic pageview tracking is automatic, custom events need to be migrated to GA4's event structure. Google Tag Manager makes this transition easier.
What happens to my Universal Analytics data after sunset?
UA properties stopped processing new data on July 1, 2023. Historical data remains accessible in read-only mode for at least 6 months (until December 2023), after which it may be deleted. Export critical data ASAP.
Is GA4 better than Universal Analytics?
GA4 is more future-proof with better privacy features, cross-platform tracking, and AI capabilities. However, it has a steeper learning curve and fewer standard reports. It's not "better" - it's different and necessary.
Can I still create a new Universal Analytics property?
No. Google stopped allowing new UA property creation in 2022. GA4 is the only option for new properties.
How long does GA4 migration take?
Basic setup: 1-2 hours. Complete migration with custom events, testing, and report building: 2-4 weeks for a typical business. Complex setups may take 2-3 months.
🎁 Final Verdict
Verdict: GA4 is Mandatory
This isn't a choice between two options - Universal Analytics is deprecated. GA4 is Google's analytics future.
Recommendation:
- If you haven't migrated: Set up GA4 immediately to start collecting data
- Export UA data: Download all historical reports and data you need long-term
- Invest in training: GA4 requires learning new concepts and interface
- Be patient: GA4 improves continuously; features missing today may arrive tomorrow
- Consider alternatives: If GA4 doesn't meet your needs, explore privacy-focused alternatives like Matomo or Plausible
Bottom Line:
GA4 represents a significant improvement in privacy, cross-platform tracking, and AI capabilities. While the transition requires effort, it's necessary and ultimately beneficial for long-term analytics success.