Essential Growth Metrics
Startups and Area 120 projects often ask me to share metrics related to user acquisition: What does it cost me to acquire users via ads? How likely is it that someone will give me notification permissions?
Here’s a list of useful growth-related metrics that you can use as a basis for estimation. I’ll try to keep these updated when I can, and will add to it over time if I find more relevant stats.
Each metric is followed by a source, and the year in which the data was collected. If no source is given, the number is from personal experience.
90-day retention of popular apps: Facebook 98%, Whatsapp 77%, Instagram retains 48%, Snap 33%. [source, 2015]
90-day retention rate of average app: 29% [source, 2018]
Cost-per-install (CPI) for a high-quality user in the US: $5 
Cost-per-install (CPI) overall worldwide: Android $0.44, iOS $0.86 [source, 2019]
Funnel Completion Rates
Average churn from adding one step to an onboarding funnel: 20% [source]
Churn for a step that requires user to sign up with email/password: 60%
Churn for a step that requires user to sign up with OAuth (FB, Google, Twitter): 50%
Churn for asking the user to re-login with email/password: 20%
End-to-end conversion on e-commerce websites: desktop 3.89%, smartphone 1.43% [source, 2016]
Average click-through rate (CTR) on push notifications: 7.8% (4.9% on iOS, 10.7% on Android). [source, 2018]
Users opting in to push notifications: iOS 43.9%, Android 91.1% [source, 2018]
Apps in the Apple App Store: 2.1M [source, 2018]
Apps in the Google Play Store: 2.6M [source, 2018]
Time for Apple to approve your App Store submission: 2 weeks
Time for Apple to approve an update to an existing app in the App Store: 48 hours