GA4 Key Events

June 5, 2025

Alright, let’s get stuck in. If you’ve been poking around Google Analytics 4 (GA4), you’ve probably noticed things are a bit different from Universal Analytics.

One of the biggest head-scratchers for many has been the whole “events” shebang and the mysterious disappearance of “conversions,” only for them to be replaced by “key events.” (and then return)

So, what’s the deal? Is it just Google playing word games, or is there something more substantial going on? Grab a cuppa, and let’s unravel this, shall we?

This article will walk you through the essentials of GA4’s event-driven world, explain what these “key events” are all about, and even touch on why you might still see “conversions” lurking about.

GA4: It’s All About the Events

First things first: GA4 thinks about data in a fundamentally different way to its predecessor. Every single interaction a user has with your website or app is now considered an “event.”

Whether someone views a page, clicks a button, downloads a file, or makes a purchase – yep, it’s an event.

This is a big shift from Universal Analytics, where we were used to dealing with things like “page hits” and a specific structure for events involving “event category,” “event action,” and “event label.” Remember trying to shoehorn your tracking into those three boxes? For instance, a video play might have had “Video” as the category, “Play” as the action, and the video’s name as the label.

GA4 simplifies this by making everything an event, each with its own set of parameters (which are basically extra bits of information about that event). Think of it like this: Universal Analytics was like a set menu with specific courses, whereas GA4 is more like a buffet where every dish is an “event,” and you can add different “parameter” side dishes to describe it.

This approach offers a heap more flexibility in how you track user interactions.

Know Your Event Types: From Automatic to Custom

Now, not all events are created equal, and GA4 has a few different flavours you’ll encounter. It can seem a bit like a pick ‘n’ mix at first, but it’s fairly logical once you get the hang of it.

Automatically Collected Events: These are the bread and butter, collected by default when you set up GA4. Things like session_start (when someone starts a new session) or page_view (when a page is viewed) fall into this category. No extra tinkering needed from your side, which is rather nice.
Enhanced Measurement Events: These are also largely automatic, but you need to give GA4 the nod to collect them. They cover common interactions like outbound clicks, site search, video engagement (video_play), and file downloads (file_download). You can toggle these on or off in your GA4 settings.
Recommended Events: Google provides a list of suggested events with predefined names and parameters for common scenarios across different industries (like e-commerce or gaming). Using these, such as login, purchase, or search, can unlock more detailed reporting capabilities now and in the future. It’s always worth checking this list before you go creating a custom event from scratch – why reinvent the wheel, eh? You can find Google’s list of recommended events here.
Custom Events: If none of the above quite fit what you need to track, then custom events are your best friend. This is where you define the event name and the information (parameters) you want to send along with it. Perhaps you want to track clicks on a specific “request a quote” button or see when users scroll halfway down a particularly important page. These are the events you’ll create yourself.

Feeling a tad overwhelmed by the choices?

Honestly, it’s mostly about starting with the automatic and enhanced ones, then looking at recommended events, and only then diving into custom events if there’s a specific gap.

Setting Up Custom Events

So, you’ve decided you need a custom event. Smashing! The generally accepted best way to get these set up is by using Google Tag Manager (GTM). GTM is a fantastic tool that lets you manage all your website tracking tags (not just GA4) without having to constantly fiddle with your website’s code. It gives you much more control and flexibility.

When naming your custom events, there’s a simple but crucial convention: use lowercase letters, with underscores instead of spaces if you have multiple words. For example, button_click or form_submission_thank_you. If you leave spaces, GA4 just won’t register it properly.

Oh, and a quick tip: if you’re sending extra custom information (parameters) along with your events (like the name of the button clicked or the form submitted), you’ll need to tell GA4 about these. You do this by setting them up as “custom dimensions” or “custom metrics” within the GA4 interface.

The Big Switch: “Conversions” are Now “Key Events”

Right, let’s tackle the elephant in the room.

You’ve set up your GA4, you’re tracking events like a pro, and then you notice that “Conversions,” a term we’ve all known and (mostly) loved, has done a disappearing act.

Instead, you’re seeing “Key Events.”

So, what exactly are these key events? In essence, they are the interactions on your site or app that you deem most important to your business organisation.

These are the actions you really care about because they signify something valuable happening – a lead, a sale, a significant engagement. For example, this could be someone landing on a “thank you” page after submitting a form, or requesting a price.

Purchase Event As standard, purchase is already set up as a key event in all GA4 properties.

This name change also ripples through to your metrics.

Where you might have previously looked at “session conversion rate,” you’ll now see “session key event rate.”

Similarly, “user conversion rate” becomes “user key event rate.”

Functionally, they measure the same thing – the rate at which sessions or users complete these important actions – but the terminology has been updated.

Does it fundamentally change how you analyse the data? Not really, once you get used to the new name.

You can read more about conversion rate metrics here.

Making an Event “Key”: Your How-To Guide

Turning one of your regular events into a key event is pretty straightforward. You don’t create key events from scratch; instead, you tell GA4 that an existing event is important enough to be flagged as ‘key’.

Here are a couple of ways to do it:

From the Events List: Once an event is being collected in GA4, you can find it in the events list (either in the Admin > Data display > Events section, or in the Reports > Engagement > Events section). Next to the event name, you’ll typically see a toggle or a menu (often a three-dot or “burger” menu) that allows you to “Mark as key event.” Flick that switch, and Bob’s your uncle!
Using the “New Key Event” Button: In the Admin > Data display > Key events section, you’ll find a button, usually labelled “New key event.” If you click this, you can type in the exact name of an event you’ve already set up (perhaps via GTM) but that might not have sent any data through to GA4 yet. This is handy if you know you want an event to be key from the get-go. Just copy the event name precisely, paste it in, and save.

Fine-Tuning Your Key Events: Counting & Value

Once you’ve marked an event as key, there are a couple of other settings you can tweak. If you go to the Admin > Key events list and click on the three dots next to a key event, you’ll see options for “Change counting method” and “Set a default key event value.”

Counting Methods

You generally have two choices for how GA4 counts your key events:

Once per event: This means GA4 will count a key event every single time that specific event occurs. So if a user completes your “contact us” form three times in one session (perhaps they forgot something the first two times!), it’ll count as three key events.
Once per session: This method counts the event as a key event only once within a particular user session, even if the user triggers the event multiple times. Using the same example, if the user submits the form three times in one session, it’ll only count as one key event for that session.

Which should you choose?

If you’re looking to maintain some sort of consistency with how Universal Analytics goals were often counted, the “Once per session” option is generally the one to go for.

However, “Once per event” can be useful if every instance of the event truly is a distinct valuable outcome.

Setting a Default Key Event Value

This is a particularly neat feature for businesses that are more lead-generation focused rather than direct e-commerce.

If you don’t have a direct purchase value attached to an event, but you know that, on average, a lead (like a “book a demo” submission) is worth a certain amount to your business (say, £100), you can assign that monetary value here. This helps you to start quantifying the value of your non-e-commerce key events within GA4.

Conversions Aren’t Entirely Extinct? The Google Ads Connection

Now, just when you thought you had it all figured out, there’s a little twist. While “conversions” have been largely replaced by “key events” within most of GA4, the term “conversions” hasn’t vanished completely. It still pops up specifically when you’ve linked your GA4 property to Google Ads.

Here’s how it works: If you import your GA4 key events into your linked Google Ads account and then mark them as “conversions” within Google Ads, GA4 will then refer to these specific actions as “conversions” in certain reports. You’ll primarily see this in the Advertising workspace in GA4, particularly in the “Conversion performance” report.

Why this distinction? It’s mainly to maintain alignment and consistency with Google Ads reporting, where these actions are indeed treated as advertising conversions. For most day-to-day users focusing purely on GA4 analytics (and not deep in Google Ads campaign management), the “key event” terminology will be what you interact with most. It’s a nuance, but one worth being aware of if you’re working across both platforms.

Why Bother With All This? The Real Importance of Key Events

So, after all that, why should you care about setting up events and marking the important ones as key? Well, it’s absolutely central to understanding how your website or app is performing against your actual business objectives.

Key events are your signposts to success. They tell you if users are doing the things that ultimately drive your business forward – whether that’s generating leads, making sales, signing up for newsletters, or engaging deeply with your content.

It’s not just about collecting mountains of data; it’s about focusing on the data points that provide actionable insights and help you make better decisions to improve your bottom line.

Wrapping It Up: Focus on What’s Key

Phew! We’ve covered a fair bit of ground there. The main takeaway is that GA4’s event-based model, while a shift from Universal Analytics, offers a more flexible and comprehensive way to understand user behaviour. The change from “conversions” to “key events” is largely a semantic one, but it emphasizes the importance of identifying and tracking those user interactions that are genuinely critical to your business success.

Don’t be afraid to get your hands dirty with events. Start with what GA4 gives you, explore the recommended options, and then build out custom events where you need them. And most importantly, make sure you’re flagging those all-important actions as key events.

Now it’s over to you.

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Author

Hello, I'm Kyle Rushton McGregor!

I’m an experienced GA4 Specialist with a demonstrated history of working with Google Tag Manager and Looker Studio. I’m an international speaker who has trained 1000s of people on all things analytics.