Why doesn't GA4 match my CRM numbers?

Because they're counting different things with different rules. GA4 counts tracked events from browsers it could see, within its attribution model and lookback windows; your CRM counts actual people and deals. Ad blockers, consent banners, cross-device journeys, and phone calls all create gaps between the two.

Some mismatch is normal and permanent. The problem is when teams treat GA4 as the source of truth for revenue — it was never designed to be one.

The fix is direction, not perfection: capture events server-side under your own domain to close the blocker gap, track calls, and reconcile against the CRM monthly so you know your measurement error instead of guessing at it.