Blended vs Paid CAC (App)

Blended CAC is total acquisition spend over every new user in a period; paid CAC is paid spend over only the users that paid spend brought in.

You compute blended by dividing all marketing cost by all new users, organic and paid together, which flatters the number because free installs from ASO, referrals, and virality drag the average down. Paid CAC isolates the marginal cost of the next bought user by counting only paid channels against only paid-attributed users. You need both: blended for whether the whole app is economic, paid for whether you can scale spend.

Spend on ads brings 400 paid installs while ASO and word of mouth deliver 600 free ones, for 1,000 new users total. Blended CAC is the ad spend split across all 1,000; paid CAC is the same spend split across only 400, so paid CAC lands about 2.5 times higher and is the honest cost of buying growth.

Blended CAC hides the scaling wall. As you push paid budget up, the cheap organic users do not scale with it, so blended stays comfortable right up until paid CAC crosses your payback threshold and unit economics quietly break. Steer acquisition on paid CAC against payback; use blended only to sanity-check the whole business.

Blended tells you if it works; paid tells you if it scales.