Short answer: A GA4 key event is an event marked as important in Analytics. A Google Ads conversion is an action Ads counts and, if primary, bids on. A key event turns into one only when imported. On 5 Nov 2026, 305 of the 886 Google Ads sites in our 1,727-site study (34.4%) listed 10 or more key events, and 42 (4.7%) marked a page view type event as key.
What is the difference?
| GA4 key event | Google Ads conversion | |
|---|---|---|
| Used for | Reporting, audiences | Reporting and, if primary, bidding |
| Created by | Marking an event as key | Ads tag, GA4 import, offline import |
| Cost of junk | Messy reports | Bids tuned to the wrong action |
GA4 "conversions" became "key events" in March 2024. A signup sent by an Ads tag and imported from GA4 counts twice.
What do sites mark as key events?
On 5 Nov 2026 we read the Google tags of 1,727 sites (1,201 B2B SaaS, 271 agencies, 255 ecommerce). GA4 writes its key event list into that tag. 886 sites had a Google Ads conversion.
| In the public Google tag | All 886 Ads sites | 684 B2B SaaS Ads sites |
|---|---|---|
| GA4 loaded | 76.6% (679) | 79.8% (546) |
| At least one key event listed | 76.2% (675) | 79.7% (545) |
| 10 or more key events | 34.4% (305) | 39.8% (272) |
A page view type key event (session_start, page_view, first_visit, scroll, user_engagement) |
4.7% (42) | 4.8% (33) |
| A login key event | 4.4% (39) | 5.4% (37) |
Sites that list key events have a median of 8 (9 for SaaS). session_start is the most common page view type, on 22 of the 886. Every visit starts a session, so as an Ads conversion it counts visits.
Across all 981 sites that load GA4, with or without Ads, 55 (5.6%) list a page view type key event. That is about 1 in 18.
From outside we can't see which key events are imported, or which actions are primary or secondary (limits).
What should be a primary Google Ads conversion?
B2B SaaS: qualified lead or opportunity from the CRM (offline import), booked meeting, trial started, payment with value.
Ecommerce: purchase with value.
Lead gen: qualified lead, not every form.
Keep off the primary list: page views and session_start, logins (customers you already have), trial ended (every trial ends), clicks before a form, scroll depth. They can stay key events.
Marking a lead form? generate_lead or form_submit. Ads shows 0 conversions? Clicks but no conversions.
How do I audit my own list?
In Google Ads, Goals, Conversions, list every primary action and its source (Ads tag or GA4 import).
Keep primary only what moves toward revenue and fires once per real conversion. Make the rest secondary. Merge duplicates.
Add values, even estimates (trial = trial-to-paid rate × first-year value).
Updated 7 Nov 2026: added the 55 of 981 GA4-site figure. 6 Nov 2026: shorter, same data. Data: our study data (key_events, ads_conversions), scanned 5 Nov 2026, distinct key event names per site. First published 4 Nov 2026. Method.
FAQ
Should I import GA4 key events into Google Ads?
Only real progress, never a step an Ads tag already tracks. That one would count twice.
How many primary conversions should I have?
Usually 1 to 4. With fifteen, Google bids on a blend of everything.
Originally published on fireshift.ai. We built Fireshift, a free scan that reads what a site sends to Google Ads and GA4 from the outside.
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