eCPI (Estimated CPI)

In one line

eCPI (Estimated CPI) is a modeled cost-per-install figure a network reports when it can't observe individual installs — as under SKAdNetwork — reverse-engineered from spend and aggregated conversion signals.

How it differs from regular CPI

Regular CPI is a straightforward calculation: cost ÷ actual installs counted. eCPI is an estimate built from a network's own modeling (SKAN aggregate conversion values, probabilistic matching, etc.) — and that modeling error varies by network and by period.

Why to be careful

eCPI is an estimate, not a count — it can diverge from your own tracked install numbers. Don't judge a channel as "cheap" on eCPI alone; cross-check against your own server-side conversion data where possible.

In practice

Optimizing iOS campaigns purely on eCPI can push budget in the wrong direction. Look at SKAN aggregate data alongside your own first-party conversion signals to confirm direction.