Glossary · Compter l’argent

Cost per acquisition (CPA)

Cost per acquisition is a campaign's spend divided by the number of customers it actually won. It is abbreviated *CPA*, and it is never judged on its own: it is judged against the margin the customer brings.

Les quatre divisions qui décident si une campagne mérite un euro de plus. The forty terms of the trade

What it is for

It turns ad spend into a sentence you can decide on: “this customer cost me €45”. It is the figure that makes two campaigns comparable when they share neither budget nor volume, and the only one that lets you say “I can raise the budget”.

How it is calculated

Spend divided by number of customers. €450 spent for 10 customers gives a cost per acquisition of €45. Mind the denominator: customers, not leads — otherwise the figure is three to ten times too flattering, depending on the trade.

The classic mistake

Comparing it with average order value instead of margin. A €210 basket at 60% margin leaves €126: a cost per acquisition of €150 looks profitable against the basket, and loses €24 per customer in reality.

Panier moyen

Trois nombres, dans le bon ordre

45 €

Coût par acquisition

450 € de dépense pour 10 clients gagnés.

126 €

Marge par vente

210 € de panier, à 60 % de marge. C’est la vraie limite.

210 €

Panier moyen

Le chiffre auquel on se compare à tort.

La dépense en face du revenu, campagne par campagne

What Subtraq does with it

The free tool /outils/calculateur-de-roas calculates it next to average order value, with a margin slider and a break-even threshold on the gauge. Nothing is sent to a server: a free tool that asks you to sign up is a lead-capture page in disguise.