Why every platform shows you different numbers.

Platforms grade their own homework.

The core misunderstanding: ad platforms do not measure your marketing. Each one counts every conversion it can claim any credit for, by its own rules, because its reporting exists to prove its own value. That is why the platform numbers added together will always exceed your actual orders. Adding them up is the one thing you should never do.

The reasons, so you can name them.

Attribution windows. Meta claims a purchase seven days after a click and one day after a view. Google Ads claims it up to thirty days after a click. Same purchase, two claims, both “correct”.

View-through conversions. Meta counts people who merely saw an ad and bought later. GA4 never counts views. This alone can explain half the gap.

Double counting. A customer who clicked a Google ad on Monday and a Meta ad on Wednesday shows up in both platforms. Fully. Each claims the whole conversion.

Different attribution logic. GA4 distributes credit across the journey with data-driven attribution; the platforms keep it all for themselves.

Reporting dates. Google Ads books the conversion on the day of the click, not the purchase. A Tuesday order from a Friday click lands on Friday.

Consent and modeling. Where consent is declined, Google models estimates, Meta aggregates, and your backend counts the real order. Three different answers to the same missing data.

Stop trying to make them match. Assign jobs instead.

The numbers count different things, so reconciling them line by line is a career-length project with no finish line. The productive move is deciding which number is for what:

Meta’s number is excellent for judging one creative against another inside Meta. It is useless for deciding whether Meta deserves budget over Google; that comparison needs one neutral ruler, which is what a clean GA4 or your warehouse is for. And the delta between systems should be known and documented once, not re-litigated in every meeting. (For the marketing-versus-finance version of this problem, see Why your dashboard never matches finance.)

The one-paragraph policy to roll out.

“We optimize inside platforms with platform numbers. We compare channels and steer budget with one agreed source of truth. We never sum platform conversions, and every known delta between systems is documented with its reason.” Put that in writing, and the weekly number debate is over.