The GA4 purchase key event on Shopify: how to mark it, import it into Google Ads, and why it does not match your orders

From conversions to key events

Google's help page on the change says: "Events that measure actions that are important to the success of your business are now called 'key events.'" A conversion "now refers to an important action that you want to use to measure the performance" of your ad campaigns. Google gives the reason as creating "a simpler and more intuitive experience in the way conversions are measured and reported across Google Ads" and Analytics.

So in GA4 you mark purchase as a key event. In Google Ads you create a conversion from it. They are two separate things, with their own settings, and Google says their counts can differ.

Shopify's own help page on GA4 still says to "Set up events and mark them as conversions in Google Analytics." It means the same step.

Is purchase already a key event?

Usually yes. Google says GA4 marks purchase as a key event by default, for web and for app. Check that the event arrives and that nothing else is marked by mistake.

1. 1In GA4, go to Admin, and under Data display select Events.
2. 2Find purchase in the Recent events tab, or search for it.
3. 3The star next to it should be filled. If it is not, click the star. Google says you must be an Editor or above to do this.

If purchase is not in the list at all, GA4 has not received one recently. That is a tracking problem, not a key event setting. Start with GA4 purchase event not firing on Shopify.

Google allows up to 30 key events on a standard property. If add_to_cart also carries a star, your key event totals mix purchases with earlier steps. Read the purchase line on its own.

Do not create a second purchase key event

Some setups add a custom event such as order_paid and mark it as a key event too. Then one sale makes two key events. Keep the star on purchase only. If two tags both send purchase itself, see GA4 duplicate purchases on Shopify.

Import the purchase into Google Ads

Google's help lists what you need before the import:

• your Google Ads and Google Analytics accounts linked;
• auto-tagging turned on in Google Ads;
• the event marked as a key event in GA4;
• at least a Marketer role in Google Analytics and admin access to the Google Ads account;
• a site that does not drop the Google click ID, for example through a redirect.

Then, in Google Ads:

1. 1Open Goals and go to Summary.
2. 2Click Create conversion action.
3. 3Select your Google Analytics property.
4. 4Select purchase and click Select events.
5. 5Click Save and continue.

Google says it can take up to 24 hours before conversion data shows in Google Ads, and that data from before the import is not included. Google also says that conversion actions created from the Google Analytics side are set as secondary. A secondary action does not drive bidding until you change it in Google Ads.

Keep one Primary purchase action. If the Google & YouTube app already created a purchase action, and you import the GA4 purchase as well, set one of them to secondary. Otherwise one sale counts twice in the Conversions column. For the ways to set up purchases in Google Ads and how to choose, see Shopify Google Ads conversion tracking.

Why GA4 shows a different number than Shopify

Shopify counts orders. GA4 counts the purchase events that reached it. The gap comes from the way between the two.

• Consent. Shopify says that in markets that require consent, usually the EEA and the UK, "web pixels run only when visitors have provided the permissions required in the pixel configuration." When a buyer declines analytics with Google's consent mode, Google says no Analytics cookies are set and cookieless pings are sent instead. These purchases can be missing or modelled.
• The browser. A browser tag reports a purchase only if it loads on the Thank you or Order status page. Ad blockers and privacy settings stop some of them. See Safari and ad blockers hide purchases.
• Orders outside the online checkout. Shopify says pixels load on the storefront, checkout, Thank you page and Order status page. An order that never goes through those pages, such as an order made at a point of sale, gives the pixel nothing to report.
• Purchases sent twice. A second tag, or a reload of the order page, can send the same purchase again. The transaction_id parameter "helps you avoid getting duplicate events for a purchase," in Google's words, so it must be the order ID in every sender. See Purchase event fires again when the order page is reopened and GA4 purchases with transaction ID (not set).
• Test orders and refunds. Test orders can reach GA4 like real ones, and a refund in Shopify does not remove the purchase from GA4. See Test orders showing up in Meta or GA4 and GA4 does not show refunds of Shopify orders.

For the full check, order by order, see GA4 shows fewer purchases than Shopify.

Why Google Ads shows a different number than GA4

Even after the import, the two tools rarely agree. Google's help gives these reasons:

• Google Ads puts a conversion on the date of the ad click. GA4 puts it on the date the purchase happened.
• Google Ads counts only purchases after an ad interaction, inside a conversion window of 1 to 90 days.
• With the counting method "One", Google Ads counts one conversion per click. With "Every", it counts all of them.
• The Conversions column shows only Primary actions. All conversions adds secondary actions and other sources.
• Imported conversions arrive up to 24 hours after they happened.

Google also says that key events and conversions can use different attribution models. And Google Ads conversions do not appear in the standard GA4 reports. For the gap between Google Ads and your orders, see Google Ads purchases don't match your Shopify orders.

For how the purchase reaches GA4 and Google Ads, see how a paid order reaches Meta, GA4 and Google Ads.

FAQ

Do I lose data when GA4 calls it a key event instead of a conversion?

No. It is a new name for the same setting in GA4. The word "conversion" now means the action in Google Ads.

Why does Google Ads show no conversions after the import?

Check that the action is not still secondary, that auto-tagging is on, and that a day has passed. Older purchases are not imported.

Where Tikra fits

Tikra sends each paid online order of your Shopify store from our server to Google Analytics 4 as a purchase, with the Shopify order ID as the transaction ID, and keeps a record for each order: what was sent, when, and the answer. When its pixel read them with analytics consent, the purchase carries the buyer's client ID and session ID. Without them, Tikra uses an ID made for the order: the revenue counts, but GA4 cannot show where the buyer came from.

Google gives no confirmation per order, so Tikra shows Google Analytics 4 orders as sent, not confirmed, and our help points you to the Realtime report for the real check. Tikra applies your customers' consent choices to every order, and in Strict mode an order is sent only with the buyer's consent. A written guarantee in our Terms covers eligible orders: at least 97 % reach each platform, fixed within 12 hours or a month's fee credited (Terms of Service, section 8).

The free diagnosis sends none of your orders anywhere. It shows your paid orders of the last 7 full days, how many came from a Meta, Google or TikTok ad, and, after a full day and 10 paid online orders, how many your shoppers' browsers reported.

Run the free diagnosis