Key Takeaways
- Formula: CPA = total campaign cost / number of conversions (leads, sales, sign-ups).
- Note: Google Ads' "cost per conversion" includes all defined conversions; "customer acquisition cost" (CAC) includes only customers who were actually acquired.
- Key Points: €15 to €60 per lead in B2C, €50 to €300 in B2B, with prices varying widely by industry.
- Rule: A CPA is good if it is lower than the margin generated by the conversion.
The CPA, cost per acquisition, is the amount spent to generate a conversion: a sale, a request for a quote, a sign-up, or a phone call. It is the key metric in online advertising because it translates a budget into results that are comparable across different channels. Google Ads refers to it as “cost per conversion”; Meta calls it “cost per result.” This article combines our two previous guides on the subject.
The formula and an example
CPA = Cost / Conversions. A Google Ads campaign that cost €1,200 and generated 40 quote requests has a CPA of €30. If one out of every four quote requests turns into a customer with a profit margin of €800, each quote is worth €200: the €30 CPA is very profitable. If one in twenty becomes a customer, each quote is worth €40, and the campaign barely breaks even.
| Campaign | Expenditure | Conversions | CPA | Value of a conversion | Verdict |
|---|---|---|---|---|---|
| Google Ads Search | 1 200 € | 40 quotes | 30 € | 200 € | Cost-effective, needs improvement |
| Meta Ads | 900 € | 12 quotes | 75 € | 200 € | Cost-effective, needs optimization |
| Display | 600 € | 2 quotes | 300 € | 200 € | Unprofitable; should be discontinued or repositioned to build brand awareness |
CPA, cost per conversion, CAC: three related concepts
| Term | What matters | Usage |
|---|---|---|
| Cost per conversion | Any conversion defined in the tool (lead, call, addition to cart, etc.) | Managing a campaign in Google Ads or Meta |
| CPA | Cost per lead or sale | Channel Comparison |
| CAC | Total cost (media, tools, salaries) per actual client acquired | Overall profitability, compared to the customer lifetime value |
The most common misconception: a CPA of €30 per lead is not the same as a cost of €30 per customer. If one out of every five leads becomes a customer, the cost per customer is €150, before adding administrative costs.
Key Figures by Sector
The typical figures observed in France in 2025–2026, across all service sectors, for a qualified lead (form or phone call):
| Sector | Average CPA per lead |
|---|---|
| E-commerce (cost per sale) | €10 to €40 |
| Services for Individuals (Tradespeople, Healthcare, Education) | €15 to €60 |
| Real Estate, Automotive | €40 to €120 |
| B2B, software, consulting | €50 to €300 |
| Insurance, finance, legal | €80 to €400 |
These figures only make sense when considered in relation to your margin: a CPA of €300 is excellent for a €20,000 contract, but disastrous for a €30-per-month subscription.
How to Lower Your CPA
- Target more precisely : exact-match keywords, negative keywords, qualified audiences, relevant geographic areas.
- Improve Ads : A higher click-through rate lowers the cost per click (via the Quality Score) and increases the volume.
- Optimize the landing page : A shorter form or a faster-loading page can double the conversion rate, thereby cutting the CPA in half for the same budget.
- Using Target CPA Bidding Once 30 monthly conversions are reached, set the target gradually.
- Exclude existing customers acquisition campaigns and turn them into customer loyalty initiatives.
The CPA is read along with its neighbors: the CPC (cost per click), the conversion rate (the percentage of clicks that result in conversions) and the ROAS (revenue per euro spent, which is more appropriate for e-commerce).
How GreenRed Can Help You
Instead of juggling multiple tools, GreenRed's Return on Investment module brings these metrics together in a single dashboard, compares them over time, and shows you which actions to prioritize. You can try it for free—no credit card required—on the page Rates.
Frequently Asked Questions
How do you calculate CPA?
Divide the total cost of a campaign (media budget, plus any management and creative costs) by the number of conversions achieved. A €1,000 campaign that generates 25 quote requests has a CPA of €40. Advertising networks automatically calculate the cost per conversion based solely on the media budget.
What is the difference between CPA and CAC?
CPA measures the cost of a conversion, often a lead. CAC (customer acquisition cost) measures the total cost of acquiring a customer, including management costs, tools, and the lead conversion rate. CAC is always higher than CPA per lead.
What Makes a Good CPA?
A CPA lower than the margin generated by the conversion, taking the conversion rate into account. If one out of every four quotes results in a customer with a margin of €800, any CPA lower than €200 per quote is profitable. Industry averages serve as a benchmark, not a target.
What is the CPA target in Google Ads?
An automated bidding strategy in which Google adjusts bids to maximize conversions at an average cost that you set. It requires at least 30 conversions per month and reliable conversion tracking to work properly.