ChatGPT Ads next to Google and Meta: counting conversions consistently across channels

Anyone running three channels knows the puzzle: Google reports 80 conversions, Meta 60, ChatGPT 40 — and the shop has 120 orders. The channel sum exceeds reality because each network counts with its own window and all claim the same purchase when the customer saw several ads. That can't be fully solved. It can be made comparable.

The default windows of the three networks

• Google Ads: 30 days after click by default, view-through depending on campaign type.
• Meta Ads: 7 days after click and 1 day after view by default.
• ChatGPT Ads: 30 days after click and 1 day after view by default — switchable to 7 or 14 days click and view-through off.

With the defaults you're comparing Google 30 days with Meta 7 days with ChatGPT 30 days. That's the most common reason ChatGPT initially looks “too good” or Meta “too bad” in channel comparisons.

Step 1: pick a common window

Agree on a window all three networks support. 7 days click and 1 day view is the lowest common denominator and, for most shops with short purchase cycles, also the more honest measure. For ChatGPT Ads you set it in Chatvertise on the Conversions page (how the windows work in detail); the selection lives in the URL and can be bookmarked for the weekly report.

Step 2: the same time basis

ChatGPT Ads can assign conversions to the day of the ad interaction or the day of the conversion. Google and Meta use the day of the ad interaction by default. For channel comparison, choose the same basis; for reconciling with the shop backend, which counts by order date, the conversion basis. You can't have both at once — decide per report.

Step 3: don't add up, hold against the truth

The honest number is the order list in the shop. Compare each channel individually against it and compute the share it claims. If the sum of claims clearly exceeds actual orders, the channels overlap — a sign the same customers are reached several times. That's not bad, but it means each channel's marginal contribution is smaller than its reported number.

What makes ChatGPT Ads special

A click in ChatGPT often comes at the end of a consultation and thus late in the buying process. That's why the click-through share is worth a look: Chatvertise shows per conversion event how many conversions come from clicks and how many from mere views. A high click share with a short window is the strongest argument a channel can make for its contribution.