A Naming Change That Caused Confusion

In March 2024, Google renamed GA4 “Conversions” to Key Events.

The reason: Google wanted to separate GA4 measurement terminology from Google Ads conversion terminology. In GA4, you mark important events as Key Events. In Google Ads, you import those Key Events and they become Conversion Actions.

They are related but distinct - and confusing the two causes tracking errors.

This article explains both clearly and shows you how to set them up correctly.

What Is a Key Event in GA4?

A Key Event is any event in GA4 that you have flagged as important.

Marking an event as a Key Event does two things:

  1. It appears in GA4 reports with special treatment (shown in Key Events column)
  2. It becomes available to import into Google Ads as a conversion action

Any event can be a Key Event - whether it was automatically collected, came from Enhanced Measurement, or was a custom event you sent.

What Is a Conversion in Google Ads?

A Conversion in Google Ads is an action you are measuring as valuable for your campaigns.

When you import a GA4 Key Event into Google Ads, it becomes a Conversion Action that:

Key rule: Not every GA4 Key Event should become a Google Ads Primary Conversion. That distinction matters enormously for bidding.

How to Mark a Key Event in GA4

Method 1: From the Events Report

  1. GA4 → Reports → Engagement → Events
  2. Find the event you want to mark
  3. Toggle the Mark as key event switch on the right

Method 2: From Admin

  1. GA4 → Admin → Key Events
  2. Click New key event
  3. Enter the event name exactly as it is sent (case-sensitive)
  4. Save

The event must already exist in GA4 (must have fired at least once) to appear in the Events report toggle. If you use the Admin method, you can pre-register an event before it has fired.

What Events Should You Mark as Key Events?

The answer depends on your business model. Here are the most important ones by type.

For Lead Generation Businesses

For Ecommerce

For SaaS / Software

Do not mark every event as a Key Event. Only mark actions that directly indicate business value or strong intent.

Primary vs Secondary Conversions in Google Ads

When you import GA4 Key Events into Google Ads, you must set each one as either Primary or Secondary.

Primary Conversions

Example: purchase for ecommerce, generate_lead for lead gen.

Secondary Conversions (Observation Only)

Example: add_to_cart, begin_checkout, page_view (if you track it).

Never set micro-conversions (add to cart, scroll, button click) as Primary in Google Ads. Smart Bidding will optimise for them instead of your actual goal - increasing volume of cheap actions rather than real results.

How to Import GA4 Key Events into Google Ads

  1. In Google Ads, go to Goals → Conversions → Summary
  2. Click New conversion action
  3. Select Import
  4. Select Google Analytics 4 properties
  5. Choose your GA4 property
  6. Select the Key Events you want to import
  7. Click Import and continue
  8. For each imported action, set:
    • Category (purchase, lead, etc.)
    • Primary or Secondary
    • Count (one vs every - use “one” for leads, “every” for purchases)
    • Conversion window (how long after a click a conversion counts)
    • Value (static value, or dynamic from the event parameter)

Count Setting: One vs Every

This is a commonly misconfigured setting.

One: Only the first conversion per click is counted. Use this for lead gen - if someone submits a form twice, you only want to count one lead.

Every: Every conversion per click is counted. Use this for purchases - a user who buys three times should count as three conversions.

Getting this wrong inflates or deflates your conversion data.

Conversion Windows

The conversion window defines how long after a click (or view) a conversion is attributed to an ad.

Defaults:

For high-consideration purchases with long decision cycles (B2B, high-ticket), extend the click-through window to 60 or 90 days.

For low-consideration or impulse purchases, 7 - 14 days is often more realistic.

A Common Setup Error: Double Counting

If you have both GA4-imported conversions and a direct Google Ads tag (gTag) tracking the same event, you will double-count conversions.

Pick one source of truth:

Do not use both for the same conversion action.

What Good Conversion Tracking Looks Like

A clean setup for a lead generation business:

GA4 Key Events:

Google Ads - Primary:

Google Ads - Secondary (Observation):

This gives Smart Bidding clean, high-intent signals while keeping informational events visible without affecting optimisation.

Final Thoughts

The Key Event → Google Ads Conversion pipeline is one of the most important setups in performance marketing.

Get it right, and Smart Bidding has accurate data to work with. Get it wrong, and you are paying Google to optimise for the wrong things.

In the next article of this series, we will cover:

The GA4 reports you actually need as a Google Ads advertiser.

Related Posts

GA4 Enhanced Ecommerce Tracking - What the Data Layer Needs to Look Like

10 min read

GA4EcommerceData LayerGTMTrackingGA4 Intro Series

Understanding GA4 Attribution - Last Click vs Data-Driven and What It Means for Your Campaigns

9 min read

GA4AttributionGoogle AdsData-Driven AttributionGA4 Intro Series

GA4 Audiences - How to Build and Export Them to Google Ads

8 min read

GA4AudiencesGoogle AdsRetargetingGA4 Intro Series
Adnan Agic

Adnan Agic

Google Ads Strategist & Technical Marketing Expert with 5+ years experience managing $10M+ in ad spend across 100+ accounts.

Need Help With Your Google Ads?

I help e-commerce brands scale profitably with data-driven PPC strategies.

Get In Touch
Back to Blog