Can I Have Both Universal Analytics and Google Analytics 4?
Navigating the major shift from Universal Analytics (UA) to Google Analytics 4 can feel daunting, sparking many questions about the right way to proceed. The most common one by far is whether you can have both versions running on your website at the same time. The short answer is yes, you absolutely can - and for a long time, doing so was considered the best practice for a smooth transition. This guide will walk you through the reasons for this "dual-tagging" strategy, how to set it up, and what to expect along the way.
The Benefits of a Dual-Tagging Strategy
Running UA and GA4 in parallel wasn't just a precautionary measure, it was a strategic move that offered several significant advantages during the migration period. Understanding these benefits helps clarify why so many businesses adopted this approach and why an understanding of both platforms remains valuable.
1. Building Historical Data in GA4
Perhaps the most critical reason for dual-tagging was that GA4 properties start with a clean slate. They do not import your historical data from Universal Analytics. By setting up GA4 early and letting it run alongside UA, you allowed it to start accumulating data immediately. This ensures that when the time comes to rely solely on GA4 for analysis, you have months - or even years - of valuable historical data to use for comparisons, trend analysis, and year-over-year reporting. Without this overlap period, you would be starting from zero, making it impossible to answer questions like, "How is this month's performance compared to this month last year?"
Free PDF · the crash course
AI Agents for Marketing Crash Course
Learn how to deploy AI marketing agents across your go-to-market — the best tools, prompts, and workflows to turn your data into autonomous execution without writing code.
2. A Safer Training Environment for Your Team
Universal Analytics and GA4 are fundamentally different. The switch involves more than just a new interface, it’s a complete shift in the data model, moving from something based on sessions and pageviews to a more flexible model built around events and users. This comes with a steep learning curve.
Dual-tagging provided a crucial safety net for teams. While marketers, analysts, and business owners were getting familiar with GA4’s new reports, terminology (like "Engagement Rate" vs. "Bounce Rate"), and a different way of thinking about user behavior, they could still rely on familiar, trusted UA reports for their regular duties. This gradual transition minimized the risk of misinterpreting data, pulling incorrect numbers for stakeholders, and feeling overwhelmed by the change.
3. Verifying and Validating Your New Data
Since the data models are different, the numbers you see in UA will not perfectly match the numbers in GA4 - and that's by design. A "user" or a "session" is measured differently in each platform. For example:
- Sessions: In UA, a session could restart at midnight or if a user arrives via a new campaign. GA4 is less likely to break up a continuous user journey, often resulting in a lower session count.
- Users: UA focuses on "Total Users" based on client ID, whereas GA4 prioritizes "Active Users," which is a better measure of an engaged audience.
By running both systems simultaneously, you can directly compare their outputs. This doesn’t mean you’re looking for them to match perfectly. Instead, you're looking for them to be directionally correct. Seeing side-by-side data helps you understand these discrepancies, build trust in your new GA4 setup, and confidently explain to your team why the numbers have changed.
4. Filling Feature and Integration Gaps
Upon its launch, GA4 lacked certain features and integrations that were staples in Universal Analytics. Many third-party reporting tools, data visualization platforms, and SaaS products had built-in connectors for UA that didn't immediately support GA4. By keeping UA active, businesses ensured their existing reporting workflows, automated reports, and connected apps continued to function without interruption while they waited for GA4's ecosystem to mature.
How to Implement Universal Analytics and Google Analytics 4 Together
There are three common methods for setting up dual-tagging on your website. The best approach for you depends on how you've implemented analytics in the first place.
Using the GA4 Setup Assistant (The Easiest Route)
Google understood the need for a seamless transition and built an assistant right into the Universal Analytics interface. This is the simplest method if you're not using a tag management system.
- Log into your Google Analytics account and go to the Admin section. Be sure you have a Universal Analytics property selected.
- In the Property column, click on GA4 Setup Assistant. It should be the first option.
- Under the "I want to create a new Google Analytics 4 property" section, click the Get Started button.
- A pop-up will appear explaining what will happen. All this process does is create a new GA4 property and, if you have the "gtag.js" snippet on your site, it will automatically enable data collection for GA4 in addition to your existing UA property. Critically, it does not change your UA property at all.
This wizard effectively handles the dual-tagging setup for you, allowing you to collect data for both properties from a single snippet on your site.
Implementing with Google Tag Manager (GTM)
If you're already using Google Tag Manager (and you should be!), setting up dual-tagging is clean, flexible, and gives you the most control. You just need to add a new tag for GA4 to fire alongside your existing UA tag.
- Create a New Tag: In your GTM workspace, go to "Tags" and click "New."
- Configure the Tag: Name it something descriptive like "GA4 - Configuration" and for the Tag Type, choose Google Analytics: GA4 Configuration.
- Enter Your Measurement ID: You'll need to get this ID from your new GA4 property. To find it, go to your GA4 account and navigate to Admin > Data Streams > Click on your web data stream. The ID starts with "G-". Paste this Measurement ID into the appropriate field in your GTM tag configuration.
- Set the Trigger: You want this new configuration tag to fire on all pages, just like your standard UA pageview tag. In the "Triggering" section, select the All Pages trigger.
- Save and Publish: Save your new tag. Be sure to use the "Preview" mode in GTM to test that both your UA tag and new GA4 tag are firing correctly before you publish the container live.
With this setup, GTM will send data to both your UA and GA4 properties simultaneously whenever a page loads.
Adding to Your Existing Code Snippet (gtag.js)
For those who have the analytics code installed directly on their website, the global site tag (gtag.js) is thankfully designed to send data to multiple destinations.
Your existing Universal Analytics gtag.js snippet will look something like this:
<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=UA-YOUR-ID-HERE"></script>
<script>
window.dataLayer = window.dataLayer || [],
function gtag(){dataLayer.push(arguments),}
gtag('js', new Date()),
gtag('config', 'UA-YOUR-ID-HERE'),
</script>To add GA4 tracking, all you need to do is add a second config line with your new GA4 Measurement ID right below the UA config line. It should look like this:
<!-- Global site tag (gtag.js) - Google Analytics -->
<script async src="https://www.googletagmanager.com/gtag/js?id=UA-YOUR-ID-HERE"></script>
<script>
window.dataLayer = window.dataLayer || [],
function gtag(){dataLayer.push(arguments),}
gtag('js', new Date()),
gtag('config', 'UA-YOUR-ID-HERE'),
gtag('config', 'G-YOUR-GA4-ID-HERE'), <!-- Add this line -->
</script>With this simple addition, the tag will now send pageview and other automatic tracking data to both your UA and GA4 properties.
Free PDF · the crash course
AI Agents for Marketing Crash Course
Learn how to deploy AI marketing agents across your go-to-market — the best tools, prompts, and workflows to turn your data into autonomous execution without writing code.
What to Expect When Running UA and GA4 in Parallel
Deploying both tracking codes is only the first step. The dual-running period is when the real work of migration happens.
1. Data Will Not Match Perfectly - And That's Okay
Re-create your key conversion actions, reporting dashboards, and tracking configurations in GA4. Critically, UA's "Bounce Rate" metric is gone, replaced by "Engagement Rate," a much more useful measure of how users interact with your site. Accepting this shift is key to adopting GA4. Instead of trying to make the numbers match 1:1, use this time to understand why they are different and get your team comfortable with the new metrics.
2. Replicate All Your Custom Tracking
Your advanced tracking configurations from UA won't magically appear in GA4. You need to manually recreate them for the new platform. This includes:
- Goals and Conversions: UA goals must be set up as conversion events in GA4.
- Event Tracking: If you track clicks, form submissions, or video plays, this logic needs to be migrated to GA4's event-based model.
- E-commerce Tracking: GA4 has a new and more detailed e-commerce schema. You will need developer assistance to re-tag your purchase funnel.
- Filters: Rules like excluding traffic from internal IP addresses need to be re-configured in your GA4 property settings.
- Custom Dimensions & Metrics: Any custom data you were sending to UA needs to be set up again in GA4 to enrich your reports.
Final Thoughts
In short, not only could you run Universal Analytics and Google Analytics 4 at the same time, but doing so via "dual-tagging" was the recommended path for a structured and low-risk migration. This strategy allowed you to build a foundation of historical data in GA4, validate your new setup, and train your team without disrupting your daily workflows. The effort invested in managing both platforms simultaneously paid off by ensuring a confident and informed transition to the new age of analytics.
Managing data across different analytics platforms - let alone your entire stack of marketing and sales tools - can quickly become tangled. At Graphed, we focus on making data analysis simple and instant. We connect to all your sources, including Google Analytics, Shopify, and your social ad accounts, allowing you to ask questions in plain English and get real-time dashboards in seconds. Instead of wrestling with data, you can have AI do the heavy lifting for you with Graphed.
Related Articles
How to Create Facebook Ads API for Claude Code
Create a Meta Marketing API access token that never expires, using a system user, so Claude Code can pull Facebook ad reports and manage campaigns.
ClickHouse vs Postgres: When to Switch to Columnar
Comparing ClickHouse vs PostgreSQL means matching storage architecture to workload. Row storage wins for transactions. Columnar wins for scan-heavy analytics.
Google Ads for Orthodontists: Get More Booked Consults
Most orthodontic Google Ads campaigns waste money on low-intent searches. The problem is structure, not the platform.