Why every ad platform claims the same conversion
Add up what your platforms report and you will often find more conversions than you had orders. That is not fraud. It is what happens when every platform is allowed to mark its own homework.
If you total the conversions reported by Meta, Google Ads and your email platform, and compare that total to the orders in your own database, the two numbers rarely match. The platform total is usually higher, sometimes by a lot.
Each platform sees a different slice
A platform reports a conversion when it can connect an order to something it showed you. Meta counts a purchase within its attribution window if the buyer saw or clicked an ad. Google does the same. Your email tool does the same. One order, three claims, three separate reports that each look internally consistent.
None of them is lying. Each is answering a narrower question than the one you are asking. The platform answers what happened after someone saw my ad. You want to know what would not have happened otherwise. Those are different questions and they have different answers.
Why it matters commercially
Double counting inflates the apparent return of whichever channel sits closest to the purchase. Retargeting and branded search look excellent because they are present at the end of almost every journey. Upper funnel work looks weak because it is present at the start and rarely gets the credit. Budget then flows toward the channels that are best at claiming credit rather than the ones creating demand.
What to do about it
Three things, in order. Reconcile platform-reported conversions against your own order or CRM records, so you know the size of the gap. Agree one definition of a conversion, written down, that finance recognises. Then price incrementality properly with a holdout test on the channels where the claim looks strongest.
None of this requires new software. It requires deciding that one number wins, and being willing to see a favourite channel look worse once it does.