CPI meaning: what is cost per install?
CPI means cost per install: what an advertiser pays each time someone installs its app. It is total spend divided by installs. Most deals count an install once the user has opened the app, not when the download starts.
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The formula is one division: CPI = total spend ÷ installs.
Example: a studio pays $4.20 per install and gets 100 installs, so it spends $420. Run it backward and you get the same answer: $420 ÷ 100 installs is a CPI of $4.20.
The number can be a price you agreed in advance or a result you work out afterward. On an offer priced per install, the two match. On a campaign bought by impression or by click, CPI is only known after the installs arrive, and it moves day to day.
“Install” sounds exact and isn’t. A store download, a first open and an install matched to a tracked click can each give a different count for the same day. Check which one your deal pays on before you compare two CPIs. The attribution rules decide which installs count as yours.
How CPI sits next to the other pricing models is in the table on the CPE page.
Advertisers can pay at install, a percent of each sale, or per level or in-app event. A charge needs a live event that matches a tap on the campaign. Publishers choose what they run, so an offer that doesn’t let them make money won’t get traffic. Game advertisers can read how it works for mobile games. Pricing each step: Choose events and what each one pays.
Questions
What is a good CPI?
It varies by country, platform and category, so no single number holds. A CPI is good when what those users do later is worth more than you paid for them, and only your own data can say that.
Is CPI the same as CPA?
CPI is CPA with one fixed action, the install. CPA can be any action you name, such as a sign-up or a first purchase.
Do I pay CPI for a user who deletes the app?
Usually yes, once the install is confirmed. That is why many advertisers also pay for steps inside the app, which shows who stays.