What is CPA?
Cost Per Action (CPA), also known as Cost Per Acquisition, is an advertising pricing model where payment is triggered by specific user actions beyond just installing an app. These actions typically include registrations, purchases, subscriptions, or other valuable conversion events.
CPA campaigns shift more risk to publishers/networks, since they only get paid when users complete meaningful actions—not just when they install.
CPA Formula
CPA = Total Ad Spend ÷ Number of Actions
Common CPA Events
- Registration: User creates an account
- First Purchase: User completes their first transaction
- Subscription: User subscribes to a paid plan
- Level Complete: User reaches a certain game level
- Deposit: User adds funds (fintech/casino)
- Tutorial Complete: User finishes onboarding
CPA vs CPI: Key Differences
| Aspect | CPI | CPA |
|---|---|---|
| Payment Trigger | App Install | Specific Action |
| Risk Level | Higher for advertiser | Higher for publisher |
| User Quality | Variable | Generally higher |
| Typical Cost | Lower per event | Higher per event |
| Best For | Volume/Scale | Quality/Value |
When to Use CPA Campaigns
- When user quality matters more than volume
- When you have clear conversion events to optimize for
- When you want to reduce risk of paying for low-quality users
- When you have enough data to set appropriate CPA targets
Setting CPA Targets
Calculate your target CPA based on lifetime value:
- Determine your average LTV per converting user
- Decide on your target profit margin
- CPA Target = LTV × (1 - Profit Margin %)