What is target CPA?
CPA (cost per acquisition) is what you spend on ads to get one sale. Target CPA is the ceiling you must stay under to keep the profit you set. It is the number you compare cost per result against in Ads Manager every day.
The formula
Max CPA = selling price − all costs − desired profit
Target ROAS = selling price ÷ max CPA
Example: a product sells for 500, costs 250, and you want 100 profit per sale. Max CPA = 500 − 250 − 100 = 150, and target ROAS = 500 ÷ 150 ≈ 3.33.
How to use the number in campaign management
- Make it your alert threshold: if cost per purchase stays above it for two days, something needs attention.
- Use it with Cost Cap: if you use Meta's cost cap bid strategy, this is the logical cap.
- Compare ads against it: an ad whose cost per sale stays above the ceiling is a candidate to pause.
If your current CPA is well under the ceiling, that's a sign you can raise the budget. Learn how to do it safely in How to Scale a Winning Facebook Ads Campaign Without Breaking It.
When is a target CPA unrealistic?
If max CPA is lower than your cost per click multiplied by the clicks you usually need for one sale, the numbers won't work. For example, CPC is 5 and conversion rate is 1%, so you need 100 clicks = 500 per sale while your ceiling is 150. Better ads won't fix that; you need a higher price or order value, or a better landing page.