5 Key GA4 Metrics Every E-commerce Store Must Track (To Grow Revenue)

Do you ever feel like logging into Google Analytics 4 (GA4) is like walking into the cockpit of a fighter jet—when all you really wanted to do was ride a bicycle?

You aren't alone.

For years, e-commerce store owners relied on Universal Analytics to quickly check bounce rates and conversion numbers. But since the forced migration to GA4, many small business owners have been left scratching their heads. The interface has changed, the metrics have been renamed, and finding simple answers ("How much money did I make from Instagram yesterday?") now requires navigating a maze of reports and explorations.

Here is the hard truth: GA4 collects more data than ever before, but more data often leads to less clarity.

If you run an online store, you don't need to monitor every single graph Google provides. In fact, doing so is a waste of your valuable time. You only need to focus on a handful of "North Star" metrics that directly impact your bottom line.

In this guide, we are cutting through the noise. We'll break down the 5 critical GA4 metrics that actually matter for your e-commerce growth—and show you exactly how to track them without pulling your hair out.

1. Engagement Rate (The "New" Bounce Rate)

If you have been looking for "Bounce Rate" in your standard GA4 reports and panicking because you can't find it, take a deep breath. It's (mostly) gone, and frankly, that's a good thing.

In the old analytics world, Bounce Rate told you the percentage of people who left your site without doing anything. But it was flawed. If a user landed on your blog post, spent 10 minutes reading every word, and then left satisfied, they were considered a "bounce." That looked like failure, even though it was a success.

Enter Engagement Rate.

Engagement Rate is the percentage of sessions that were "engaged sessions." Google defines an engaged session as one that:

• Lasts longer than 10 seconds, OR
• Has a conversion event (like a purchase or signup), OR
• Has at least 2 pageviews

Why it matters for e-commerce

Engagement rate tells you the quality of your traffic.

• Low Engagement Rate? You might be targeting the wrong audience with your ads, or your landing page might be broken or confusing.
• High Engagement Rate? People are stopping, looking, and interacting.

What to aim for

For e-commerce sites, an engagement rate between 40% and 60% is generally considered healthy. If you are seeing rates below 30%, it's time to audit your product pages or check page load speeds.

2. Purchase Revenue (Total & Trend)

This seems obvious, right? You run a store; you need to know how much you sold.

But in GA4, simply seeing a "Total Revenue" number isn't enough. You need to look at Purchase Revenue trends compared to user acquisition.

One of the biggest traps store owners fall into is celebrating a spike in traffic while ignoring a flatline in revenue.

How to analyze it

Don't just look at the big number on the dashboard. You need to break Purchase Revenue down by Traffic Source.

• Is your revenue coming from Organic Search (SEO)?
• Is it coming from your Paid Social ads?
• Is it coming from your Email Newsletter?

If you see that Paid Search is driving 50% of your traffic but only 5% of your Purchase Revenue, you are bleeding money. GA4 allows you to see this attribution, usually under Reports > Life cycle > Acquisition > Traffic acquisition.

3. Add to Carts vs. Checkouts (The Funnel Health)

Tracking sales is great, but tracking almost sales is where you make your money back.

Two distinct metrics you need to watch like a hawk are:

1. Add to Carts
2. Begin Checkout

These metrics function as the "pulse" of your shopping experience.

The Scenario

Imagine you had 1,000 visitors yesterday.

• 50 people added an item to their cart.
• Only 2 people started the checkout process.

That is a massive drop-off. It tells you that customers want the product (they added it), but something stopped them before they even typed in their address.

• Are your shipping costs hidden until the end?
• Is the "Checkout" button hard to find?
• Did a pop-up annoy them?

By monitoring the ratio between Add to Carts and Begin Checkout, you can identify technical glitches or friction points that are killing your conversion rate.

4. User Acquisition by Source / Medium

"Where did you come from?"

If you cannot answer this question about your customers, you cannot scale your business.

In GA4, the User Acquisition report is your best friend. It differs slightly from "Traffic Acquisition." User Acquisition focuses on how a user found you for the first time.

Why it matters

Let's say a customer buys a $100 pair of shoes today via a direct link in your email newsletter.

• Traffic Acquisition gives credit to "Email."
• User Acquisition might tell you they originally found you via a "Google Search" three weeks ago.

If you only look at Traffic Acquisition, you might think, "Wow, email is my best channel, I'll stop doing SEO." That would be a mistake, because SEO is what brought them into your world in the first place.

Keep an eye on First user source / medium. Identify which channels are feeding the top of your funnel, even if they aren't the ones closing the immediate sale.

5. Conversion Rate (Session Conversion Rate)

Finally, the metric that summarizes efficiency: Session Conversion Rate.

This is simply the percentage of sessions that resulted in a purchase.

Average Benchmarks

E-commerce conversion rates vary wildly by industry, but generally:

The GA4 Twist

GA4 sometimes defaults to "User Conversion Rate" (percentage of users who bought). This is useful, but for daily optimization, Session Conversion Rate is often more actionable. It helps you understand if a specific marketing campaign you ran today resulted in action today.

To find this, you often have to customize your standard reports to add the "Session conversion rate" column, as it's not always there by default. (Yes, another GA4 quirk).

The Problem: Finding These Metrics is Painful

Knowing what to track is step one. Actually tracking them in GA4 is step two—and that's where most people give up.

To check these five metrics in the standard GA4 interface, you usually have to:

1. Log in.
2. Navigate to "Reports."
3. Click "Acquisition" for traffic data.
4. Click "Monetization" for revenue data.
5. Click "Engagement" for event counts.
6. Create a custom "Exploration" tab if you want to see them all in one view.
7. Filter the dates manually every time.

It's friction. It's time-consuming. And because it's annoying, you probably don't do it as often as you should.

The Solution: Just Ask

Conclusion

You cannot improve what you do not measure. But you also cannot improve anything if you spend all your time measuring and no time taking action.

By focusing on these 5 key metrics—Engagement Rate, Purchase Revenue, Cart vs. Checkout, User Acquisition, and Conversion Rate—you simplify your strategy. You stop worrying about vanity metrics and start focusing on growth.

And if you want to make that process even easier? Try Gentle today. Stop fighting with the GA4 interface and start having a conversation with your business data.