Paid Search
CPA (Cost Per Acquisition)
CPA is the average cost to win one conversion, calculated as total spend divided by the number of conversions.
It is the metric most directly tied to profitability, since it shows what each customer or lead actually costs to acquire. For example, spending 10,000 baht to generate 20 leads is a CPA of 500 baht. A campaign with cheap clicks but high CPA usually points to a weak landing page or poor targeting.
Reported CPA and true CPA diverge whenever lead quality varies, which it usually does. A campaign at 400 baht per lead that closes one in twenty costs more per customer than a campaign at 900 baht that closes one in four, and the platform reports the opposite. Closing this gap requires sending outcomes back into the ad platform, either through offline conversion imports or by tracking a qualification event instead of the form submission. Without that, smart bidding optimises toward cheap leads, and cheap leads are always available somewhere.
Example
A campaign spends 60,000 baht and produces 40 enquiries: 1,500 baht CPA. Sales closes 25%, so a customer costs 6,000 baht against 45,000 lifetime value: profitable with room to scale. The same numbers with a 9,000-baht product would be a loss. The target CPA was set by working backwards from close rate and value, not by comparing against the previous month.
Frequently asked questions
- What is a good CPA?
- Whatever is comfortably below the profit on a converted customer. There is no universal benchmark: a CPA of 3,000 baht is excellent for a property enquiry and disastrous for a low-margin product. Work backwards from customer value and close rate.
- Why is my CPA rising?
- Common causes are increased competition bidding up clicks, ad fatigue reducing click-through, a landing page that converts worse than before, tracking that has started missing conversions, or automated bidding still learning after a major change.
Related terms
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