What N-day retention means
N-day retention is the umbrella term for any retention figure measured a set number of days (N) after install. Day 1, Day 7, Day 14, and Day 30 retention are all N-day retention values at different windows. The install day itself is Day 0, and N counts calendar days from there. The three most watched windows, Day 1, Day 7, and Day 30, are shorthand for onboarding health, early-week habit formation, and durable monthly retention.
Every N-day retention number shares the same cohort logic. Installs are grouped by their install day, and each install must have had a fair chance to reach Day N before it is counted. An install from three days ago belongs in the Day 1 cohort but not yet in the Day 7 cohort, so each window has its own denominator.
The three definitions behind an N-day number
"Day 7 retention" is ambiguous until you say how a return is counted, because the same window can be measured three ways. Classic retention counts a user only if they opened the app on exactly Day N. Cumulative retention counts a user who opened the app at least once between Day 1 and Day N. Rolling retention counts a user who opened the app on Day N or any later day. The same cohort can produce three different Day 7 numbers, so always confirm which definition a figure uses before comparing it to anything.
Why N-day retention matters for growth
N-day retention is the backbone of cohort analysis and one of the clearest signals of user quality. Because it is measured per cohort, it lets you compare the January install cohort against the February one on equal footing, and, when connected to attribution data, compare retention across acquisition sources. A channel that delivers strong Day 30 retention is far more valuable than a cheaper channel whose users churn in the first week, even if the cheaper channel looks better on cost per install alone.
In Linkrunner, N-day retention is available at Day 1, Day 7, Day 14, and Day 30 (windows vary by method) and can be broken down by campaign, ad set, and creative through the Campaign Reporting API.