GA4 key events and Google Ads conversions are two systems for the same idea, and the point where they meet, the GA4 to Google Ads import, is where accounts most often end up counting twice. This guide explains both, what the import actually does, and a simple rule for which to use for each conversion.
Key Events in GA4
A key event is any event you mark as important under Admin, then Events. GA4 then reports it in conversion columns, uses it in attribution reports, and makes it available for export to Google Ads. There is no limit on web; mark the outcomes that matter and leave engagement events unmarked.
Key events carry whatever parameters the event has, including value and currency if you sent them. For purchase, GA4 uses the ecommerce value. For generate_lead, send value and currency explicitly so the key event has a value to import.
The Google Ads Link and Import
Link GA4 to Google Ads under Admin, then Product links. Then in Google Ads, under Goals, then Conversions, then New conversion action, then Import, then Google Analytics 4 properties, select the key events to import. Each becomes a conversion action in Google Ads with its own settings: primary or secondary, count, window and value source.
What the import does well:
- Brings GA4-only actions into Google Ads without extra tags: content reads, video completes, secondary engagement.
- Makes GA4 audiences available for remarketing and observation.
- Lets small sites with few conversions use one measurement setup.
What it does less well than native tags:
- Latency: imported conversions can take most of a day to appear.
- Attribution: GA4 attributes at session level and Google Ads re-attributes on import, which can differ from click-level native counting.
- Enhanced Conversions: GA4 does not pass user-provided data into Google Ads conversions the way a native tag does.
- Consent and modelling behave differently between the two products.
A Decision Rule
| Conversion | Use |
|---|---|
| Purchase with value | Native Google Ads tag with transaction ID and Enhanced Conversions |
| Qualified lead, booking, call | Native Google Ads tag with Enhanced Conversions |
| Trial start, signup | Native tag if it drives bidding; import if secondary |
| Engagement such as content_read, video_complete | GA4 import as secondary |
| Anything tracked only in GA4 | GA4 import |
Native for anything primary; import for anything secondary or GA4-only.
Setting Up a Native Tag Alongside GA4
The same dataLayer event feeds both. A GA4 Event tag sends purchase to GA4; a Google Ads Conversion Tracking tag sends the conversion to Google Ads; both fire on the same trigger. GA4 keeps its key event for reporting, Google Ads has its native conversion for bidding, and no import exists for that action. The Google Ads Conversion Tracking guide on this site covers the tag.
Removing a Duplicate
If an action exists as both an imported key event and a native tag:
- In Google Ads, open the imported conversion action and set it to secondary, then after a few days of confirming the native action records correctly, remove the import.
- Do not delete the key event in GA4; it is still useful for GA4 reporting.
- Check Smart Bidding campaigns the following week; their conversion counts should halve for that action and their bids will recalibrate.
Audiences: The Other Half of the Link
With the link active, GA4 audiences become Google Ads audience segments:
- Cart abandoners:
add_to_cartwithoutpurchasein 7 days. - Guide readers:
content_readin the last 30 days. - Returning customers:
purchasein the last 180 days, for exclusion from prospecting or for upsell. - High-intent leads:
form_startwithoutform_submit_success.
Create them under Admin, then Audiences in GA4, and they appear in Google Ads under Audience manager within a day. Audiences need a minimum size before they can be used for targeting.
Verifying the Setup
- In GA4, Admin, then Events, confirm the key event toggles.
- In Google Ads, Goals, then Conversions, confirm each action's source: Website for native, Google Analytics 4 for imported, with no action represented twice.
- In the Google Ads link in GA4, confirm personalised advertising is enabled for audiences.
- After a week, compare conversions per action between GA4's advertising reports and Google Ads; expect Google Ads to be lower, since it counts only ad-driven conversions, but not double.
Outcome
GA4 reports every key event across every channel, Google Ads bids on fast, Enhanced Conversions-enabled native conversions, secondary actions arrive through the import without extra tags, and nothing is counted twice.