Glossary

CPA (Cost per Acquisition)

CPA (cost per acquisition, also cost per conversion) is the average amount you spend to get one conversion. It's the efficiency metric for lead and signup campaigns: as long as a customer is worth more than their CPA, the campaign makes economic sense.

Formula: CPA = Cost ÷ Conversions

How to read it

Set a target CPA from the business side (margin, customer lifetime value), not from what the account historically achieved. Alerts on CPA deviations catch problems earlier than eyeballing dashboards.

Where it misleads

Optimizing CPA to the floor kills volume: the cheapest conversions come first, and scaling always raises marginal CPA. The question is the acceptable CPA at the volume you need.

Related terms

Conversions →

Conversions count how often users completed the action you defined as valuable (a purchase, lead form, call, or signup) after interacting with your ad. Conversions are the metric campaigns are ultimately judged by, because they connect ad spend to business outcomes.

Cost / Spend →

Cost (or spend) is the total amount an ad platform charged for a campaign, ad group, or account in the selected period. It's the denominator of every efficiency metric (CPC, CPA, ROAS) and the number that has to match the client's media budget.

ROAS (Return on Ad Spend) →

ROAS (return on ad spend) is the revenue generated per unit of ad spend: a ROAS of 4 means €4 of tracked revenue per €1 spent. It's the core efficiency metric for e-commerce campaigns, connecting spend directly to the money it brought back.

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