Key Events: Track the Actions That Matter in GA4

Key events are the events in Google Analytics 4 (GA4) that you flag as especially important to your business, such as a purchase, a demo request, or a newsletter sign-up. They are what GA4 used to call conversions.

This page explains what key events are, why Google renamed them, how they relate to Google Ads conversions, how counting works, and exactly how to set them up, along with the mistakes that most often distort the numbers.

What are Key Events?

GA4 records nearly everything as an event: page views, scrolls, clicks, form submissions, purchases. A key event is simply an event you have marked as a measure of business success. Google's help center describes it as an event that measures an action particularly important to your business, and any event you collect can be marked as one.

Until early 2024, GA4 called these "conversions." In March 2024, Google renamed them key events. Search Engine Land reported that the change was meant to address long-standing confusion caused by GA4 and Google Ads counting "conversions" differently. Existing GA4 conversions were converted to key events automatically, with no action needed.

The word "conversion" did not disappear. Google now uses it for actions that measure ad campaign performance and feed bidding. According to Google's events and key events documentation, the flow is event, then key event, then conversion.

Why Key Events matter

Key events are how GA4 connects traffic to outcomes. They power metrics such as session key event rate, which is GA4's version of a conversion rate, and they let you compare channels, campaigns, and landing pages by results rather than visits.

That matters for SEO and AI visibility. If you want to know whether organic traffic or AI referral traffic produces leads, you need key events configured correctly. In May 2026, Google added an AI Assistant channel to GA4's default channel group, according to the GA4 release notes, which makes it easier to see key events from chatbot referrals alongside other channels.

The limit: key events only measure what you tell GA4 to measure. If tracking is broken or you mark the wrong events, every downstream report inherits the error.

How Key Events work

Events, key events, and conversions

An event is any tracked interaction. A key event is an event you have marked as important; it appears in GA4's standard reports and explorations. A conversion is created from a key event for use in Google Ads, which requires a linked Ads account. Creating a Google Ads conversion from a key event also creates a matching conversion in GA4 that both platforms share. Conversions are reported in Google Ads and in GA4's Advertising section, not in GA4's standard reports.

Default key events and limits

Per Google's setup guide, GA4 marks purchase as a key event automatically for web and apps, plus several app events such as first_open. Standard properties can mark up to 30 events as key events, and Analytics 360 properties up to 50. Default key events do not count toward the limit.

Counting method

Each key event has a counting method. "Once per event," the recommended setting, counts every time it fires in a session. "Once per session," labeled legacy, counts it only once per session. If a user submits a form three times in one visit, the first records three key events and the second records one.

Timing

Marking an event as a key event only affects data from that point forward. It does not rewrite history. Standard reports can take up to 24 hours to reflect a new key event, while Realtime shows it within minutes.

Key Events in practice: an example

A hypothetical home services company wants to track leads. Its site already sends a generate_lead event when a quote form is submitted and a click_to_call event when someone taps the phone number.

The team marks both as key events. Within a day, the Traffic acquisition report shows key events by channel, and the team can see that organic search drives most quote requests while AI assistant referrals are small but growing. They link Google Ads and create a conversion from generate_lead only, because that is what they want campaigns to optimize for. Calls stay as a key event for reporting.

How to set up Key Events in GA4

Pick the actions that matter. Choose a short list of outcomes tied to revenue or pipeline, such as purchases, qualified form submissions, or bookings. Avoid marking every click.
Make sure the event is collected. Confirm the event fires correctly using GA4's Realtime or DebugView reports before you rely on it.
Mark an existing event. In Admin, under Data display, open Events. Find the event in the Recent events list and click the star icon to mark it as a key event. This needs Editor access or higher.
Or create one in advance. For an event not yet collected, click Create event on the same page, enter the exact event name, turn on Mark as key event, choose a default value and counting method, then save. This needs Marketer access or higher.
Check the counting method. Use once per event for most cases. Choose once per session only when repeat completions in one visit should count as one.
Connect to Google Ads if you advertise. Link your Ads account and create conversions only from key events you want campaigns to bid on.
Validate after 24 hours. Compare key event counts with your CRM or order system to catch duplicates or missing data.

Common mistakes and misconceptions

"Key events and Google Ads conversions are the same number." Not necessarily. A key event only becomes a conversion when you create one from it in Google Ads, and the two can differ in attribution and counting settings.

"Marking an event fixes past data." It does not. Key event status applies only from the moment you set it, so set up tracking before campaigns or site launches.

"More key events give better insight." Marking page views or scrolls as key events inflates key event rates and hides the outcomes that actually matter.

"GA4 conversions were removed." They were renamed and refocused. Your old GA4 conversions became key events, and "conversions" now refers to advertising measurement.

Key Events vs. Google Ads conversions

Key events are GA4's measure of important actions across all traffic sources, used for behavioral and channel reporting. Google Ads conversions are created from key events and used to measure ad performance and optimize bidding. Think of key events as the full list of outcomes you track and conversions as the subset you hand to Google Ads.

How Butter approaches Key Events

We start by agreeing on which actions actually represent business value, then confirm those events are tracked and marked correctly before reporting on any channel. Clean key events are the foundation for judging whether SEO, AI visibility, or ads work is paying off.

Butter Analytics connects website performance with 85+ tools in one dashboard, so key event data can sit next to search, ad, and CRM data. Fundamentals first: a few well-defined key events beat dozens of noisy ones.

Frequently asked questions

When did GA4 change conversions to key events?

Google made the change in March 2024. Existing GA4 conversions were automatically renamed key events, and "conversions" now refers to key events shared with Google Ads for campaign measurement.

How many key events can I have in GA4?

Standard GA4 properties can mark up to 30 events as key events, and Analytics 360 properties up to 50. Events GA4 marks as key events by default, such as purchase, do not count toward that limit.

Why are my key events not showing in GA4 reports?

Standard reports can take up to 24 hours to show new key events, and they only include data from after you marked the event. Also check that the event name matches exactly and that the event is actually firing.

Do key events count in Google Ads?

Not automatically. You need a linked Google Ads account and must create a conversion from the key event before Google Ads uses it for reporting or bidding.

Sources and further reading

KEEP LEARNING

100 SEO and GEO terms explained in plain English.

Browse the full glossary →