GA4 Key Events vs Conversions on Shopify: What the 2024 Rename Changed

TL;DR

GA4's old "Conversions" metric is now called "Key events." A "conversion" in Google's current language is a Google Ads conversion, created by importing a GA4 key event into a linked Ads account [1]. Nothing about your tracking changed; the labels did, and one practical consequence trips up Shopify merchants: the GA4 key-event count and the Google Ads conversion count for the same purchases will not match. That is by design. GA4 counts the key event on the day it happened under GA4's own attribution, while Google Ads counts the imported conversion by the date of the ad click inside its conversion window, with its own counting rules and modeled conversions on top. Mark one event as a key event, purchase, and reconcile the two counts over a full conversion window rather than day by day.

Key Takeaways

• GA4 renamed "conversions" to "key events" in 2024. In Reports and Explorations you now look for "Key events," not "Conversions" [1].
• A "conversion" now means a Google Ads conversion: a key event imported into a linked Google Ads account to measure and optimize campaigns [1].
• You mark a key event in GA4 under Admin → Data display → Events → toggle "Mark as key event," which needs an Editor or Marketer role [2].
• An event must be a key event in GA4 before Google Ads can import it as a conversion action [4].
• Mark only purchase as a key event on a standard store. Marking browse events like add_to_cart inflates the metric and, if imported, feeds mid-funnel noise into Smart Bidding.
• The GA4 key-event count and the Google Ads conversion count differ on purpose: Ads counts by ad-click date within a 1 to 90 day window (default 30), GA4 by event date, each under its own attribution [4].
• On Shopify, purchase is the reliable key event because WeltPixel Conversion Tracking sends it server-side from the order webhook, so it lands even when the browser pixel is blocked.

What did the 2024 GA4 rename actually change?

Google renamed the GA4 metric "Conversions" to "Key events" [1]. Google announced the change in March 2024. A key event is an event you have flagged as important to your business, a purchase, a signup, a lead. That is the same idea the old "conversion event" carried; only the name moved.

What Google did with the freed-up word "conversion" is the part that causes confusion. A "conversion" is now reserved for Google Ads. In Google's current model you measure important actions in GA4 as key events, and when you want Google Ads to optimize toward one of those actions, you import it into Ads, where it becomes a conversion [1]. So the same purchase can be a key event in GA4 and a conversion in Google Ads, and those are two separate counters kept by two different products.

For a Shopify merchant the takeaway is small but real: reports that used to say "Conversions" now say "Key events," and if a colleague talks about "conversions," you need to know whether they mean the GA4 metric (now key events) or the Google Ads metric (still conversions). The rest of this article is about those two counters and why they disagree.

How do you mark a key event in GA4?

You mark a key event in the GA4 Admin. Go to Admin → Data display → Events, find the event in the list, and turn on the "Mark as key event" toggle [2]. If the event does not exist yet, use Admin → Data display → Key events → New key event and enter the event name so GA4 starts counting it the next time it arrives [2]. You need an Editor or Marketer role on the property to do either [3].

Marking is not retroactive in the way people expect: GA4 treats matching events as key events going forward, and it does not rewrite historical data. So mark the event before you need clean history, not after. One detail specific to how WeltPixel Conversion Tracking works: the app sends the purchase event to GA4 for you, but it does not mark it as a key event. Marking is a GA4 setting you own; the app's job is to make sure the event arrives reliably.

How does a key event become a Google Ads conversion?

A GA4 key event does not reach Google Ads on its own. Three things have to be true. First, your GA4 property and your Google Ads account are linked. Second, the event is a key event in GA4, because Google Ads can only import events that are already marked [4]. Third, you create a conversion action in Google Ads from that Analytics event, under Goals → Conversions → Summary → New conversion action → Import → Google Analytics 4 properties [4].

At import you choose a counting method. "Every" counts every conversion after an ad interaction, which is what you want for sales, and "One" counts a single conversion per interaction, which suits leads [4][5]. Once imported, Google Ads treats that purchase as a conversion it can bid toward. This is also the moment the counts start to diverge, which is the next question.

Why don't the key-event count and the Google Ads conversion count match?

They measure the same purchases with different clocks and different rulebooks, so they are supposed to differ. Three causes stack up.

Attribution is the first. GA4 counts a key event under the property's attribution model and books the event on the day it happened. Google Ads counts its conversion against the ad click that led to it and books it on the click date, which can be days earlier. The mechanics of attribution models are in GA4 attribution models, data-driven vs last click; the point here is that two systems attributing the same sale assign it to different days and different sources.

The conversion window is the second. Google Ads counts an imported conversion only if the purchase falls inside the conversion window after the ad click, a setting between 1 and 90 days that defaults to 30 [4]. A purchase 45 days after the click counts as a GA4 key event but not as a Google Ads conversion under a 30-day window. The third is modeling: Google estimates key events it cannot observe directly and folds them into the count [6], so the two systems' totals include different estimates. Add the counting method and import timing, and the honest operator rule is to reconcile the two over a full conversion window, never day by day, and to expect Google Ads to land lower. This is a different comparison from Google Ads versus your Shopify order count, which has its own causes in why Google Ads reports fewer conversions than Shopify.

Which Shopify events should you mark as key events?

Mark purchase, and usually nothing else. WeltPixel Conversion Tracking sends a full set of GA4 events from a Shopify store, view_item, add_to_cart, begin_checkout, and the rest of the browse funnel, and every one of them is a legitimate event. That does not mean every one should be a key event. Marking add_to_cart as a key event inflates your "key events" metric with mid-funnel actions, and if you import that into Google Ads you train Smart Bidding on carts instead of sales. The full list of events GA4 expects on an ecommerce store, and what each one is for, is the GA4 recommended ecommerce events canon.

There are narrow exceptions. A store optimizing a lead flow might mark a signup, and a subscription store might mark begin_checkout for a specific analysis. But for measuring revenue and feeding Google Ads, purchase is the key event that matters, and keeping the list short keeps both your GA4 reporting and your Ads bidding clean.

Why is purchase the reliable key event on Shopify?

A key event is only useful if it fires every time and only once. On Shopify, purchase clears both bars because of how it is sent. WeltPixel Conversion Tracking fires purchase server-side from Shopify's order webhook, not from the browser, and sends it to GA4 through the Measurement Protocol [7]. Because it comes from the confirmed order rather than a thank-you page, it lands even when the browser pixel is blocked by an ad blocker, dropped during a Shop Pay redirect, or lost to an abandoned tab. The reasons the browser is unreliable for the purchase are in Conversion API vs browser pixel.

Firing once matters just as much. A browser-only thank-you-page setup double-counts when a shopper refreshes the confirmation page. The server-side purchase is recorded as sent for each order, so retries and concurrent webhook deliveries do not double-count, and it carries a transaction_id that lets GA4 collapse any duplicates. The result is one clean key event per order, which is the precondition for the GA4 key-event count and the imported Google Ads conversion to reconcile at all.

FAQ

Is a key event the same as a conversion?

Not anymore. In GA4 the metric formerly called "conversions" is now "key events." The word "conversion" now refers to a Google Ads conversion, which is a key event you import into a linked Google Ads account [1]. Same underlying action, two product-specific names.

Do I need to import every key event into Google Ads?

No. Import only the key events you want Google Ads to optimize toward, which for most stores is purchase. Importing browse events like add_to_cart feeds mid-funnel signals into Smart Bidding and usually hurts performance.

Why does Google Ads show fewer conversions than my GA4 key events?

Because Google Ads counts by ad-click date inside a conversion window (default 30 days) and only credits purchases that followed an ad click, while GA4 counts every key event on its event date under GA4's own attribution [4]. Reconcile the two over a full conversion window, not day by day.

Which role do I need to mark a key event?

An Editor or Marketer role on the GA4 property. Viewers and Analysts can see key events but cannot create or mark them [3].

Does WeltPixel Conversion Tracking set up key events for me?

No. The app sends the GA4 events, including the server-side purchase, but marking an event as a key event is a setting you control in the GA4 Admin. The app makes the event reliable; you decide which events count.

Track a purchase key event that fires every time

Key events are only worth marking if the underlying event is reliable, and on Shopify the purchase event is the one most likely to be lost to ad blockers and Shop Pay redirects. WeltPixel Conversion Tracking sends purchase to GA4 server-side from Shopify's order webhook, deduplicated by transaction_id, so the key event you mark and import into Google Ads is counted once per order. Add it from the App Store: https://apps.shopify.com/weltpixel-conversion-tracking?utm_source=blog&utm_campaign=073

Sources

1. Google Analytics Help, "[GA4] Conversions vs. key events in Google Analytics." https://support.google.com/analytics/answer/13965727 (accessed 2026-07-06).
2. Google Analytics Help, "[GA4] Create or modify key events." https://support.google.com/analytics/answer/12844695 (accessed 2026-07-06).
3. Google Analytics Help, "[GA4] Mark events as key events." https://support.google.com/analytics/answer/13128484 (accessed 2026-07-06).
4. Google Ads Help, "Create conversions from Google Analytics events in Google Ads." https://support.google.com/google-ads/answer/2375435 (accessed 2026-07-06).
5. Google Ads Help, "Measure web key events from Google Analytics properties." https://support.google.com/google-ads/answer/9520128 (accessed 2026-07-06).
6. Google Analytics Help, "[GA4] About modeled key events." https://support.google.com/analytics/answer/10710245 (accessed 2026-07-06).
7. Google Analytics Help, "[GA4] Measurement Protocol." https://support.google.com/analytics/answer/9814495 (accessed 2026-07-06).