CPI vs CPA vs CPM: App Ad Pricing Models
CPM, CPI and CPA describe what you pay for: impressions, installs or actions. Knowing where the risk sits is how you buy media that actually pays.
Key takeaways
- CPM bills per impression, CPI per install, CPA per action; risk shifts to you as you move down the funnel.
- Optimize to the metric closest to value (actions and value events), not the cheapest install.
- Most platforms now bill on impressions while optimizing toward your value goal.
CPM, CPI and CPA are three ways of pricing the same media, and the difference is mostly about who carries the risk that a click turns into a valuable user. Understanding that is the key to not overpaying for hollow metrics.
What each means
CPM charges per thousand impressions, CPI per install, and CPA per defined action such as a purchase or signup. As you move from CPM to CPA, you are paying for outcomes further down the funnel.
Where the risk sits
On CPM you carry all the conversion risk: pay for views and hope they install and convert. On CPA the platform carries more of it, pricing on the action. That risk transfer is usually reflected in the rate you pay.
Optimize to value
Cheap installs are a trap if they never convert. Optimize toward the deepest reliable value event you can feed the platform, because a higher cost per install that delivers paying users beats a low one that does not.
How modern buying works
In practice most channels bill on impressions while their algorithms optimize toward your chosen value goal, with SKAN shaping what is measurable on iOS. You set the value target; the system prices the inventory to chase it.
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