Cherry Seed

Why doesn't GA4 match Facebook Ads?

Quick Answer

GA4 and Facebook use different tracking methods, attribution windows, and data collection. GA4 loses 30-40% to ad blockers; Facebook CAPI bypasses them. GA4 uses last-click attribution by default; Facebook credits itself for view-through conversions. Same sale, different counting logic.

Full Answer

Why GA4 and Facebook numbers differ: Data collection differences:

  • GA4: Client-side JavaScript (blocked by 31% of users)
  • Facebook CAPI: Server-side (bypasses ad blockers)
  • Result: Facebook sees conversions GA4 misses Attribution window mismatch:
  • GA4: 90-day click window (default)
  • Facebook: 7-day click, 1-day view (default)
  • Conversion at day 10: GA4 counts, Facebook doesn't Attribution model differences:
  • GA4: Data-driven (distributes credit)
  • Facebook: Self-attributing (gives itself credit when possible)
  • Same conversion: Different platforms claim it View-through counting:
  • Facebook counts: User saw ad, didn't click,...

Sources

Programmatic Access

GET https://seresa.io/wp-json/cherry-tree-by-seresa/v1/seeds/98

Cite This Answer

Cherry Tree by Seresa - https://seresa.io/seed/common-tracking-problems/numbers-never-match-s1