CAC
Also: Customer Acquisition Cost
CAC (customer acquisition cost) is total acquisition spend divided by the number of customers acquired in the same period. In mobile UA it is usually reported per install (CPI) or per paying user, and the two differ by the payer rate.
CAC = Total acquisition spend ÷ New customers acquired
Fully loaded CAC includes creative production, tooling, and the team, not just media. Most UA reporting uses media-only CAC because that is what changes when you move budget; keep the two labeled.
For subscription apps the meaningful CAC is per paying subscriber, since that is the unit that generates revenue. It will be several times the CPI.
Related terms
In Roasy
Roasy computes this across every ad network, Adjust, and RevenueCat on one screen — real revenue, cohort windows, and the same definition everywhere.