What is CPI?
Cost Per Install (CPI) is a mobile advertising pricing model where advertisers pay a predetermined amount each time their app is installed by a user. It's the most common pricing model in mobile user acquisition because it directly ties advertising spend to measurable outcomes.
Unlike impression-based (CPM) or click-based (CPC) models, CPI ensures advertisers only pay when they achieve their primary goal: getting the app on a user's device.
CPI Formula
How CPI Works
The CPI model operates through a straightforward process:
- Ad Display: Your ad is shown to users across ad networks, social platforms, or publisher apps
- User Engagement: A user clicks on your ad and is directed to the app store
- Installation: The user downloads and installs your app
- Attribution: The install is tracked and attributed to the specific campaign
- Payment: You pay the agreed CPI rate for that install
Average CPI Rates by Category
| App Category | iOS CPI (US) | Android CPI (US) |
|---|---|---|
| Casual Gaming | $1.50 - $3.00 | $0.80 - $2.00 |
| Mid-Core Gaming | $3.00 - $6.00 | $1.50 - $4.00 |
| Social Casino | $4.00 - $8.00 | $2.00 - $5.00 |
| Fintech | $5.00 - $15.00 | $3.00 - $10.00 |
| E-commerce | $2.00 - $5.00 | $1.00 - $3.00 |
| Health & Fitness | $2.50 - $6.00 | $1.50 - $4.00 |
Factors Affecting CPI
1. Geographic Location
CPIs vary dramatically by country. Tier-1 markets (US, UK, Canada, Australia) command premium rates, while emerging markets like India, Brazil, and Southeast Asia offer lower CPIs but potentially different user quality.
2. Platform (iOS vs Android)
iOS users typically cost 40-60% more to acquire than Android users, but often show higher engagement and monetization rates.
3. App Category
High-LTV categories like fintech and gaming have higher CPIs due to increased competition and user value.
4. Seasonality
CPIs spike during Q4 holiday season and major events, sometimes increasing 30-50% above baseline.
💡 Pro Tip: Beyond CPI
While CPI is important, focus on the metrics that matter for profitability: CPA (Cost Per Action), ROAS (Return on Ad Spend), and LTV (Lifetime Value). A low CPI is worthless if those users never engage or monetize.
CPI vs Other Pricing Models
- CPI vs CPA: CPI pays for installs; CPA pays for specific post-install actions (registration, purchase, etc.)
- CPI vs CPM: CPI is performance-based; CPM pays per 1,000 impressions regardless of outcome
- CPI vs CPC: CPI pays for installs; CPC pays for clicks to the app store
Optimizing Your CPI
To achieve better CPI rates while maintaining quality:
- Test multiple ad creatives to find top performers
- Segment campaigns by geography and optimize separately
- Use video ads which often drive higher conversion rates
- Implement A/B testing on app store pages
- Partner with performance-focused ad networks like ClicksFlyer