Retention
Retention is the share of new people who come back to your app after a given number of days, such as the next day, a week later or a month later.
Also called Day 1 retention, Day 7 retention, Day 30 retention, D1, D7, D30.
In plain words
3 in 10 new people came back to Fern the next day, and 1 in 9 a month later.
How Apparent would say it about Fern, an example app in the live demo.
How it's worked out
People who started on a day and came back on day N ÷ people who started that day. Day 1 is the next day, day 7 a week later, day 30 a month later.
Good to know
Retention tells you whether people found what they came for. Downloads can be bought or lucky; people coming back can't.
The curve always drops fast at first and then flattens. The flat part matters most: those are the people who made your app a habit. If it never flattens, everyone eventually leaves.
Compare like with like. Retention for people who came from a feature in the App Store often differs from those who came from search, and a new version can change it. That's why it's usually read by cohort: everyone who started in the same week.
Some tools count "came back on exactly day 7", others "came back on day 7 or later". The second gives bigger numbers. Know which one you're looking at before comparing apps.
Try it with your own numbers: Retention calculator.
Where the number comes from
Your app's own events, because the app has to see each person come back. The stores don't report it per person.