This is super common, here’s why you see the gap:
Different Attribution Windows:
Facebook counts conversions up to 7 days after a click or 1 day after a view by default. Shopify only counts the sale when it actually happens in that time window.
Cross-Device Attribution:
Facebook may track someone who clicked on mobile and purchased later on desktop. Shopify often can’t link those sessions together.
Modeled Conversions:
Facebook uses statistical modeling to estimate conversions lost to iOS 14.5+ tracking restrictions, so it reports higher numbers than Shopify’s raw orders.
Deduplication & Filters:
Shopify may filter out test orders, canceled orders, or duplicates, while Facebook might still count them.
It’s normal for Facebook’s reported purchases to be higher. They use broader attribution rules and modeling. To compare more closely, align attribution windows (like 1-day click) and understand that some discrepancy will always remain.
