Glossary

CPA — cost per acquisition

CPA is the cost of acquiring a paying customer or a completed action, downstream of CPL. How it is calculated and why it is not the same as CPL.

CPA (cost per acquisition) is the cost of obtaining one acquisition — usually a paying customer, sometimes a completed action.

CPA = ad spend ÷ acquisitions

CPA vs CPL

CPLCPA
Countsleadscustomers (or completed actions)
Position in the funneltopbottom
Depends onthe ad and the pagethe ad, the page and the sales process

CPA is downstream of CPL: you cannot have a good CPA with a bad CPL, but you can absolutely have a good CPL and a bad CPA — cheap leads that never buy.

The relationship is:

CPA = CPL ÷ lead-to-customer rate

If your CPL is €10 and 20% of leads become customers, your CPA is €50. A creative with a €6 CPL and a 5% close rate has a CPA of €120 — twice as expensive as the “more expensive” lead.

Why it is hard to attribute

CPA requires knowing which customer came from which ad, which means joining sales data to attribution data. That join only works if the lead left the ad system carrying its source — see lead routing.

Last updated: 2026-09-21

FAQ

Is CPA always about sales?+

Not necessarily. Some platforms use CPA for any defined action, which makes it ambiguous. In this glossary it means a completed sale or a paying customer, unless stated otherwise.

Keep reading

CPL — cost per leadCPL is the cost of acquiring one lead. Here is how it is calculated, why the platform number differs from reality, and which one to trust.ROAS — return on ad spendROAS is revenue divided by ad spend. What it measures, why it is a poor fit for lead generation, and how it hides the difference between creatives.

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