Metric guide · Product
Day 30 retention
Short answer
Day 30 retention is the share of new users who are still active about 30 days after they first used a product. Sondola measures it as the share of new users, grouped in rolling 90-day windows, who returned on day 30 or later with any app activity. This unbounded definition reads higher than strict day-30 retention.
The formula
D30 retention = new users active on day 30 or later ÷ new users in the group × 100
Unit: Percent. Better when it goes up.
How to calculate it
- Choose the group, such as all new users first seen in a 90-day window.
- Choose the return rule: exactly on day 30, within a window around it, or on day 30 or later.
- Count users in the group who meet the return rule.
- Divide by the size of the group and multiply by 100, leaving out users who are not yet 30 days old.
Mistakes that distort it
Returning on day 30 or later is a looser rule than returning on day 30 itself, so it produces a much higher number. Published day 30 figures use the stricter rule and group users by install date, so they do not fit this measure.
A group of installs from an attribution tool and a group of first-seen users from product analytics count different people. Keep the source of the group fixed.
Users who joined less than 30 days ago cannot have returned on day 30 yet. Including them pulls the rate down.
Where Sondola reads it from
Sondola reads this metric from Amplitude and Mixpanel, with the source and period on every reading. Each reading keeps where it came from, the period and the date it was recorded, and you can download all of it at any time.
See all 34 integrations →Questions
Should I track day 7 or day 30 retention?
Both. Day 7 shows whether new users form an early habit, and day 30 shows whether it lasts. Sondola also defines a D7 metric with the same any-activity rule.
Does any activity mean the same as a core action?
No. Opening the app counts as any activity, while a core action is the specific thing your product exists to do. Core-action retention is stricter and usually lower.
Related metrics
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