Key Events (formerly Conversions)

In March 2024, Google renamed the GA4 feature previously called “Conversions” to Key Events. This change clarifies the distinction between GA4 measurement data and Google Ads conversion goals.

Why the rename?

Google made this terminology shift to avoid confusion between two different systems:

• GA4 Key Events: Actions you mark as important in GA4 Admin. These are tracked as custom event conversions within GA4 reporting.
• Google Ads Conversions: Conversion goals defined in Google Ads. These can be imported from GA4, but they’re a separate system for bid optimization and campaign performance.

The old term “Conversions” blurred this distinction. The new “Key Events” label makes it clear that you’re marking events that matter to your business, independent of any Google Ads integration.

How to mark events as key events

Navigate to Admin > Data Collection and Modification > Events, then:

1. Find the event you want to mark as key (e.g., purchase, sign_up, form_submit)
2. Click the event name
3. Toggle Mark as key event to ON
4. Click Save

Once marked, the event is counted in your GA4 property’s key event metrics and appears in reports under the “Key events” metric.

Tip

You can also mark an event as key directly while editing event parameters in the Conversions tab (deprecated UI), but the recommended approach is via the Events interface.

Key event limits

Limit	Value
Key events per property	30

30 key events sounds like a lot, but in complex implementations with many forms, lead sources, and purchase types, it fills up. Be selective. Reserve key events for events that represent genuine business value:

• purchase
• lead_form_submission
• phone_call_click
• schedule_demo
• free_trial_signup
• checkout_complete

Do not mark every interaction event as a key event. Button clicks, page views, and micro-engagements create noise without analytical value.

If you need to track more than 30 important actions:

• Consolidate lower-priority events into broader categories (e.g., “engagement” instead of individual micro-interactions)
• Use separate GA4 properties for different business lines
• Rely on BigQuery export for detailed event analysis beyond the 30-event limit

Default key events

GA4 automatically marks two events as key events for all new web properties:

• first_visit — fires when a user visits your site for the first time
• purchase — fires when a purchase occurs (if you send this event)

For app properties, first_open is also pre-marked.

You can unmark first_visit if you do not want to treat new user acquisition as a key event in your campaign reporting. However, for properties with Google Ads linked and conversion-based bidding, removing first_visit from key events can affect Smart Bidding performance.

How GA4 counts key events

This is where GA4 differs significantly from Universal Analytics goals.

UA goal counting: each goal fires at most once per session. If a user completed a purchase 3 times in one session, UA counted 1 goal completion.

GA4 key event counting: by default, key events are counted once per event, per session. If a user triggers purchase 3 times in one session, GA4 counts 3 key events.

This means:

• High-frequency events (page views, button clicks) should usually not be marked as key events — each occurrence counts
• Events that can legitimately occur multiple times per session (multiple purchases) count correctly
• Events that should only count once per session (newsletter signup) may overcount if the event fires multiple times

Key event deduplication for purchases

For the standard purchase event, GA4 deduplicates based on transaction_id. If the same transaction_id is sent multiple times (e.g., from both client-side and server-side tags), GA4 counts it as one key event.

For other events, there is no built-in deduplication. If form_submission fires twice for the same form in one session, GA4 counts 2 key events. For events that should only count once per user, implement deduplication in your tracking code rather than relying on GA4:

// Check if user has already signed up before firing the key event
function trackNewsletterSignup() {
  if (!localStorage.getItem('newsletter_signed_up')) {
    gtag('event', 'newsletter_signup', {
      signup_location: 'footer'
    });
    localStorage.setItem('newsletter_signed_up', 'true');
  }
}

Key events and Google Ads bidding

When GA4 is linked to Google Ads, you can import GA4 key events into Google Ads for conversion-based bidding:

1. In Google Ads, go to Tools → Measurement → Conversions → Import → Google Analytics 4 properties
2. Select the GA4 key events to import
3. These are treated as conversions in Google Ads and become available for Smart Bidding (Target CPA, Target ROAS, Maximize Conversions)

Caution

Use “primary” vs. “secondary” conversion designation in Google Ads. Primary conversions affect bidding; secondary conversions are reported but do not influence bidding. Only use high-intent, high-reliability events as primary conversions. If GA4 double-counts a key event due to an implementation issue, your Smart Bidding will be affected.

Common mistakes

Marking page views as key events

This creates an enormous key event count that is essentially meaningless for campaign optimization. Standard reports show key event rate as “key events / sessions” — if page views are key events, your “key event rate” becomes 4-8x per session on average.

Not deduplicating purchase events

Sending purchase from both the client (thank-you page) and server (payment confirmation) doubles your transaction count and inflates revenue. Choose one source. Server-side is more reliable; use the Measurement Protocol with transaction_id to deduplicate if you use both.

Using key events for funnel steps instead of metrics

Marking “add to cart”, “begin checkout”, AND “purchase” as key events means your key event count includes every funnel step, not just completions. Use a Funnel exploration for funnel analysis. Reserve key events for the terminal action.

Ignoring the 30 key event limit

When you have more than 30 events you want to track as important actions, you must prioritize. Keep key events for events that drive bidding decisions and business reporting. Use custom dimensions and explorations for events that need analysis but not key event tracking.

Viewing key events in reporting

Key events appear in multiple GA4 reports:

Conversions report (now shows key events)

Navigate to Reports > Monetization > Conversions (or your property’s equivalent). You’ll see:

• Key event name (column)
• Key events (count of how many times the event fired)
• Key event conversion rate (percentage of sessions with that key event)
• Segmentation by dimensions (source, medium, campaign, etc.)

Real-time reporting

The real-time dashboard shows key events firing in real-time, broken down by dimension.

Funnel reports

In funnel analysis, you can select key events as conversion steps. The funnel will calculate drop-off rates between those events.

Custom reports

When building custom reports, key events are available as a metric alongside other GA4 metrics like sessions, users, and engagement rate.

GA4 key events vs. Google Ads conversions

The two systems are related but distinct:

Aspect	GA4 Key Events	Google Ads Conversions
Defined in	GA4 Admin	Google Ads Account
Purpose	Track important actions in GA4	Optimize bids and measure campaign ROI in Ads
Import path	GA4 properties are linked to Ads accounts; key events can be imported as Ads conversions	Google Ads imports them, or you create native Ads conversion tracking
Counting	Each key event fire = 1 count	Ads uses last-click or data-driven attribution by default
Reporting visibility	GA4 reports	Ads campaigns, conversion value, ROAS

When you link a GA4 property to Google Ads, you can import GA4 key events as Google Ads conversion actions. However, they remain independent systems with different attribution logic.

Impact on reporting and API queries

UI reporting changes

The GA4 UI uses “key events” language throughout:

• The “Conversions” metric in older templates is now labeled “Key events”
• Filters and segments reference “key event” instead of “conversion”
• Custom reports use the “Key event” metric dimension

BigQuery API impact

In BigQuery, the underlying event structure hasn’t changed. Key events are still regular GA4 events exported to the events_* table.

To query key events in BigQuery:

-- Count key events by event name
SELECT
  event_name,
  COUNT(*) AS key_event_count,
  COUNT(DISTINCT user_pseudo_id) AS users
FROM `project.analytics_PROPERTY_ID.events_*`
WHERE event_name IN ('purchase', 'sign_up', 'form_submit')  -- Your marked key events
  AND _TABLE_SUFFIX BETWEEN '20240101' AND '20240131'
GROUP BY event_name
ORDER BY key_event_count DESC

The GA4 Reporting API returns key events in the same way as before; the change is purely nomenclature.

Google Analytics API (Data API) impact

When querying the Google Analytics Data API (v1beta), key events are available as metrics. Example:

POST https://analyticsdata.googleapis.com/v1beta/properties/YOUR_PROPERTY:runReport
{
  "property": "properties/YOUR_PROPERTY_ID",
  "dateRanges": [{"startDate": "2024-01-01", "endDate": "2024-01-31"}],
  "metrics": [{"name": "keyEvents"}],
  "dimensions": [{"name": "eventName"}]
}

Migration checklist for teams

If your team documented GA4 integration around “conversions,” update your docs and processes:

• Audit all internal documentation that references “GA4 conversions” and update to “GA4 key events”
• Update dashboard titles and descriptions (e.g., “Conversion Funnel” → “Key Event Funnel”)
• Notify stakeholders of the terminology shift to avoid confusion with Google Ads conversions
• Review your 30-event limit and consolidate if you’re approaching the cap
• If you import GA4 key events to Google Ads, document that Google Ads conversions are separate objects
• Update API documentation (BigQuery, GA Data API) to reference key events where applicable
• Verify filters and segments in saved reports still work (they should; the underlying logic is unchanged)

Common questions

Are my existing conversions automatically renamed to “key events”?

Yes. If you were using the Conversions feature before March 2024, they are now called Key Events in the UI. The underlying event data and limits are unchanged.

Can I have key events without Google Ads?

Yes. Key events are a GA4-only feature. You can mark events as key regardless of whether you have a Google Ads account or link GA4 to Ads.

Do I need to change my event collection code?

No. Your gtag.js or Google Tag Manager setup should not change. You still send events the same way; the only difference is how GA4 Admin labels them.

Why the 30-event limit?

The limit keeps GA4 properties focused on the most important actions and prevents over-instrumentation. For fine-grained analysis of all events, export to BigQuery.

Related articles

Attribution Settings How attribution models affect key event attribution in GA4 reports.

Google Ads Conversion Tracking Set up and verify Google Ads conversions imported from GA4 key events.

BigQuery Event Export Export GA4 events to BigQuery for custom analysis beyond the 30 key event limit.