CPI (Cost Per Install) — the average cost of one mobile app install through advertising.
This metric is used when promoting apps and mobile games. CPI helps determine how much it costs an advertiser to acquire a user at the installation stage.
CPI is calculated using the formula:
CPI = Advertising expenses / Number of installs
For example, if $1 000 was spent on advertising over a certain period and 2 000 installs were received, the CPI would be $0,50.
What CPI depends on
The cost per install can vary significantly even for similar apps. It is affected by:
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GEO;
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advertising platform;
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iOS or Android;
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competition for the audience;
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app category;
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the quality of the advertising and the app page in the store;
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targeting settings.
Therefore, you should not compare the CPI of different campaigns based only on the cost per install. A hypothetical $2 per install may be an expensive result for one GEO and a good one — for another.
In addition, a low CPI does not necessarily mean that the advertising is performing well. You can get many cheap installs, but if people open the app once and leave, do not register, make purchases, or deposit, such traffic is unlikely to deliver the desired result.
Therefore, CPI is usually evaluated together with users' subsequent actions: registrations, purchases, subscriptions, deposits, and other in-app conversions.
