Calculate your cost per install (CPI) for mobile app campaigns. Measure effective CPI including post-install activation and retention for true user acquisition cost.
Cost per install (CPI) is the primary metric for mobile app advertising campaigns. Every major platform — Facebook, Google, TikTok, Apple Search Ads — can deliver app installs, but the cost and quality vary dramatically.
However, raw CPI tells only part of the story. Many installs come from users who never open the app, or open it once and churn. The effective CPI accounting for activation rate (users who complete onboarding) and retention rate (users who remain after 7 or 30 days) reveals the true acquisition cost per valuable user.
This calculator computes both the raw CPI and the effective CPI adjusted for post-install behavior. It helps you compare campaigns on the metric that matters: cost per retained, activated user, not just cost per download.
Quantifying this parameter enables systematic comparison across campaigns, channels, and time periods, revealing opportunities for optimization that drive sustainable business growth. This analytical approach empowers marketing teams to run more efficient campaigns, reduce wasted ad spend, and continuously improve the customer acquisition funnel over time.
Raw CPI doesn't reflect user quality. This calculator adjusts for activation and retention to show the true cost per valuable user, helping you optimize mobile user acquisition budgets across platforms. This quantitative approach replaces gut-feel decisions with data-backed insights, enabling marketers to optimize budgets and maximize return on every dollar invested in campaigns.
CPI = Ad Spend ÷ Installs Activated Users = Installs × Activation Rate Retained Users = Activated Users × Retention Rate Cost Per Activated User = Spend ÷ Activated Users Cost Per Retained User = Spend ÷ Retained Users
Result: $2.00 CPI, $13.33 cost per retained user
$10,000 ÷ 5,000 installs = $2.00 CPI. With 60% activation, 3,000 users actually use the app ($3.33 each). With 25% 30-day retention, only 750 users remain ($13.33 each). The true cost per valuable user is 6.7x the headline CPI.
App install advertising is one of the largest categories of digital ad spend, but the headline CPI metric hides significant quality variation. Two campaigns with identical $2 CPI can have vastly different outcomes if one has 60% activation and the other has 30%.
On average, 30–50% of app installs never result in a meaningful app open. Users install and forget, or open once and never return. This gap between install and activation is the biggest hidden cost in mobile marketing. Improving activation rate compounds the value of every dollar spent on acquisition.
Facebook app install campaigns: $1–$3 CPI. Google UAC: $1–$4. Apple Search Ads: $2–$5. TikTok: $0.50–$2. Snapchat: $1–$3. Each platform attracts different user quality. Lower CPI platforms may not deliver lower cost-per-retained-user.
Your target CPI should be derived from LTV: if average user lifetime value is $20 and you want a 3x LTV:CPI ratio, your target CPI is $6.67. But use effective CPI (adjusted for activation and retention) in this calculation for accuracy.
CPI varies hugely: casual gaming $0.50–$1, e-commerce $1–$3, fintech $3–$10, subscription apps $2–$8. iOS is typically 2–3x more expensive than Android. The "good" CPI depends on your LTV — as long as CPI < LTV, acquisition is profitable.
Raw CPI only measures the download cost. Many installs never result in engaged users. Effective CPI accounts for what percentage of installs actually use and retain the app, giving the true cost of acquiring a valuable user.
Optimize your onboarding flow: reduce steps, add progress indicators, show value immediately. Ensure your ad creative accurately represents the app. Send push notifications reminding users to complete setup. A/B test onboarding variations.
Average app activation (completes onboarding): 40–70%. Day-1 retention: 25–40%. Day-7 retention: 10–20%. Day-30 retention: 5–15%. Social and gaming apps tend toward lower retention; utility and fintech toward higher.
Optimize for cost per in-app event (registration, purchase, subscription) once you have enough data. Facebook, Google, and TikTok all support "app event optimization" that targets users more likely to become retained users, improving effective CPI.
iOS CPI is typically 2–3x higher than Android due to smaller audience and Apple's privacy controls (ATT). However, iOS users tend to have higher LTV, better retention, and higher purchase rates, often justifying the higher CPI.