CPICost Per Install
CPI is the cost to acquire one mobile app install. It's the dominant KPI for mobile UA campaigns on Meta, TikTok, and AppLovin.
CPI = Total Ad Spend / Total InstallsWhat does CPI actually mean?
Cost Per Install (CPI) is the canonical metric for mobile user acquisition. It measures total ad spend divided by the number of installs attributed to that spend over the chosen attribution window.
CPI varies wildly by vertical: hypercasual games tend to sit at the cheap end, while subscription and fintech apps are among the most expensive installs to buy. Markets matter too. Tier 1 (US, UK, Canada, Australia) CPIs are typically several times higher than Tier 3.
Modern UA teams optimize for CPI alongside ROAS or LTV-to-CAC ratio rather than CPI alone. A $10 CPI is great if your LTV is $100 and disastrous if your LTV is $5. Because CPI swings so much by market and vertical, judge new creative against your own account's recent CPI rather than industry averages.
Example
A campaign spent $3,000 on Meta UA and drove 600 installs. CPI = $3,000 / 600 = $5.
When it matters
CPI is the dominant primary KPI for mobile UA. Pair it with LTV or early-cohort ROAS so cheap installs don't hide low-value users.
Related terms
ASO
ASO is the practice of improving an app's visibility and conversion rate in the App Store and Google Play through metadata, screenshots, and keywords.
ATT
ATT is Apple's iOS opt-in framework: apps must ask permission before tracking users across other apps and websites.
SKAdNetwork
SKAdNetwork is Apple's privacy-preserving framework for mobile attribution. It provides aggregated, delayed conversion data without exposing user IDs.
MMP
An MMP is a third-party tool (AppsFlyer, Adjust, Singular, Branch) that handles mobile app attribution across ad networks, including SKAN and probabilistic modeling.
LTV
LTV is the total revenue or profit a single customer generates over their entire relationship with the business.
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