Collect the matching inputs.
Select the purchase conversion action and document attribution windows. Deduplicate transactions and separate leads or add-to-cart events from actual orders.
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Acquisition · CPACost per acquisition.
Cost per acquisition.
Put a price on the conversion you want.
Cost per acquisition divides campaign spend by attributed conversions. In this guide the conversion is a completed purchase, including purchases from existing customers.
Start with your numbers.
CPA calculator
01 / The definitionWhat is
What is
cost per acquisition?
Cost per acquisition divides campaign spend by attributed conversions. In this guide the conversion is a completed purchase, including purchases from existing customers.
Ad-platform CPA may include repeat buyers, modeled conversions and overlapping claims from other platforms. Fully loaded CAC has a narrower new-customer denominator and broader costs.
02 / The measurementA clear formula.
A clear formula.
A useful comparison.
CPA =Campaign spend ÷ Attributed purchases
Read the result in context.
Compare the same platform, conversion action and attribution model. Use order contribution to judge economic viability.
Document the comparison.
Keep the reporting dates, population, exclusions and calculation with every result. Show underlying counts as well as the average or rate, so a small sample does not look more conclusive than it is.
Illustrative example
From inputs to insight.
- Campaign spend
- 5,000
- Attributed purchases
- 200
- CPA
- €25.00
€25 per attributed purchase. This is not necessarily €25 per newly acquired customer.
Try your numbers ↑03 / Industry benchmarksContext first.
Context first.
Targets second.
Compare the same platform, conversion action and attribution model. Use order contribution to judge economic viability.
Use the source’s population and measurement rules to decide whether the comparison applies to your store.
Google Ads median CPA · USD
External context| Segment | Reported result |
|---|---|
| Apparel & accessories | $25.40 |
| Beauty | $25.39 |
| Home & garden | $38.94 |
Source: Triple Whale Google Ads benchmarks ↗. August 2025–July 2026. Platform-attributed acquisition cost; this is not fully loaded new-customer CAC.
04 / Clerk customer evidenceReal stories.
Real stories.
Clear measurement limits.
We have not verified a published Clerk customer case with a quantified cost per acquisition result matching this page’s definition.
What would count as useful evidence?
A case reporting campaign spend and attributed purchases, with the time window and comparison method. General revenue growth or a related engagement metric does not establish this result.
Customer stories describe individual implementations. They are not industry benchmarks, guarantees or standardized causal tests.
05 / Put it into practice
Put a price on the conversion you want.
Improve the path from a relevant ad to a relevant product, and track whether lower CPA comes from new or returning buyers.
06 / Common questionsA little more
A little more
clarity.
How do I calculate cost per acquisition?
Campaign spend ÷ Attributed purchases. €25 per attributed purchase. This is not necessarily €25 per newly acquired customer.
What should I check before comparing results?
Ad-platform CPA may include repeat buyers, modeled conversions and overlapping claims from other platforms. Fully loaded CAC has a narrower new-customer denominator and broader costs.
What is a good cost per acquisition?
Compare the same platform, conversion action and attribution model. Use order contribution to judge economic viability.
Does a higher attributed result prove incremental growth?
No. Attribution connects an interaction with an outcome under a reporting rule. To estimate what a change added, compare randomly assigned treatment and control groups using the same eligible population and a predefined measurement window.
Keep learning
Connect the numbers.
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