How to Measure Cohort Retention in Excel

Read a cohort table: month-3 retention for one sign-up cohort, a weighted month-1 rate that ignores immature cohorts, and the best cohort.

You will learn to

• Calculate retention for one cohort and month
• Calculate a weighted retention rate that skips cohorts without data yet
• Find the cohort with the best retention

How it works

A cohort is a group of users who signed up in the same month. A cohort table shows how many of them were still active one, two and three months later; retention is active users ÷ original cohort size. Comparing cohorts shows whether product changes are making people stick around longer.

Cohort tables are triangular: newer cohorts haven’t reached later months yet, so those cells are blank. When averaging retention for a month, only include cohorts that have data — =SUM(C2:C6)/SUMIFS(B2:B6,C2:C6,"<>") — otherwise the blanks drag the average down and make retention look worse than it is.

=E2/B2