CTR, CPC, CPM, CPA, CVR, ROAS: which metric is for what in ChatGPT Ads

A dashboard full of abbreviations only helps if you know which number answers which question. Here are the metrics ChatGPT Ads provides through the API and that Chatvertise shows on the overview in two KPI rows — base and efficiency metrics.

The base: impressions, clicks, spend, conversions

• Impressions: how often your ad was shown in a conversation.
• Clicks: how often someone clicked the ad and landed on your landing page.
• Spend: what that cost you, in account currency. The API returns decimal amounts; Chatvertise converts them and shows them with the currency.
• Conversions: how many target actions (purchase, lead, sign-up) were credited to the ad — depending on the attribution window and only available in daily or total view.

Efficiency: CTR, CPC, CPM

CTR (click-through rate) is clicks divided by impressions. The API returns it as a fraction, Chatvertise shows a percentage: 0.0267 becomes 2.67%. A low CTR usually means ad and conversation don't match. CPC (cost per click) is spend per click — the metric for traffic campaigns. CPM (cost per mille) is spend per 1,000 impressions — the metric for reach campaigns. Both hang directly on your max bid.

Outcome: CPA, CVR, ROAS, revenue

CPA (cost per acquisition) is spend per conversion — the number you compare with your margin. CVR (post-click conversion rate) is conversions divided by clicks; it measures how well the landing page does its job. ROAS (return on ad spend) is attributed revenue divided by spend: a ROAS of 4 means every euro spent brought four euros in revenue. The attributed revenue itself comes from your conversion events with a value — without values in tracking, ROAS stays empty.

Which metric for which goal

• Reach and brand: impressions and CPM. CTR as a quality signal.
• Traffic: clicks and CPC. CVR shows whether the traffic is any good.
• Sales or leads: CPA and ROAS. Everything else is a means to an end.

Two pitfalls

First: compare CPA and ROAS only with the same attribution window — otherwise you're comparing counting methods. Second: at product level there are no conversions and therefore no CPA per product; use conversion reporting by event for that. All efficiency metrics are an extra fetch in Chatvertise; the base KPIs always load with them.