GA4 shows more purchases than Shopify: how to find duplicate purchase events
Updated · TagGap
Quick answer: If GA4 shows more purchases than Shopify has orders, something sends the same purchase twice, often two integrations at once, or purchases with different or empty transaction ids so GA4 cannot tell they are the same order. Find transaction ids with more than one purchase, then remove the extra sender.
The usual causes
- Two integrations both send purchases: for example Shopify’s Google & YouTube app and a GTM or gtag setup in Customer events or the theme.
- Purchases sent without a
transaction_id, or with a session or random value, so the same order looks like different purchases. - The same GTM container or Google tag loaded twice on the page.
- A legacy setup that fires on the Order status page, which the shopper can revisit.
Find the duplicates
- In GA4 Explore → Free form, add Transaction ID as a dimension and Ecommerce purchases as a metric, sorted descending.
- Any transaction id with more than one purchase is a duplicate.
(not set)with many purchases means ids are missing entirely. - In Shopify, open Settings → Customer events and list every app and custom pixel that can send a purchase to Google.
- Run the free TagGap scan to see whether a Google tag or GTM container loads twice on your storefront.
- Keep one sender for GA4 purchases, make sure it uses the Shopify order identifier as
transaction_id, and remove or disable the others.
Why it matters
Duplicates inflate revenue and conversion rate in GA4 and in any Google Ads goal imported from it, so campaigns look better than they are and bidding overspends. TagGap counts duplicates per destination and shows the affected orders with the ids received.