What Is Cpa Marketing? CPA is sometimes referred to as "cost per acquisition" or "cost per action", which has to do with the fact that many CPA offers by advertisers are about acquiring something. Image Source Formula to calculate cost per acquisition: Cost per acquisition (CPA) is calculated as: cost divided by the number of acquisitions. So for example, if one spends £150 on a campaign and gets 10 "acquisitions" this would give a cost per acquisition of £15. ...