Planning your ChatGPT Ads budget: the simple ROAS math

“How much should I put into ChatGPT Ads?” is the most common question before launch — and four numbers answer it: budget, CPC, conversion rate and average order value. Here's the math, once by hand.

The chain: budget → clicks → orders → revenue

• Clicks = budget ÷ CPC. €1,000 at a €0.80 CPC yields 1,250 clicks.
• Orders = clicks × conversion rate. At 2.5% that's ~31 orders.
• CPA = budget ÷ orders — here around €32 per order.
• Revenue = orders × order value. At a €60 AOV: ~€1,875 revenue, i.e. a ROAS of 1.9.

The number that matters most: your break-even ROAS

Whether a ROAS of 1.9 is good depends on your margin. Break-even ROAS = 1 ÷ margin: at a 30% margin you need at least 3.3 — at 50%, 2.0 is enough. Only above that threshold does the campaign make money. In the example above, at a 30% margin the campaign would still lose money — your levers are CPC (better ads), conversion rate (better landing page) or AOV (bundles).

Run it with your numbers

Our free budget & ROAS calculator does exactly this math interactively — type your numbers, see the result instantly, no login: chatvertise.com/en/tools/roas-calculator. And once the campaign is live, Chatvertise shows CPC, CPA and ROAS from your account in real time — so you stop calculating with assumptions and start using your actual numbers.