Cohort Revenue
What one signup cohort is really worth as retention decays month over month.
Your numbers
Results
How it works
Month-N revenue = cohort × ARPU × retention^(N−1). Cumulative revenue = the sum of every month's decayed revenue.
A cohort is a group of users who signed up in the same period, tracked together over time. Cohort thinking beats blended metrics because it separates the question "are we acquiring more?" from "are the ones we acquired sticking?" — a growing top line can hide cohorts that evaporate in three months.
The classic mistake is projecting revenue as users × ARPU × months with no decay. At 90% monthly retention, a cohort's month-6 revenue is already down ~41% from month 1; the flat projection overstates the half-year total by a wide margin.
Worked example
500 users sign up, pay $30/month, and retain at 90% month over month. Over 6 months the cohort generates $15,000 + $13,500 + $12,150 + … ≈ $70,284 in total, with only ~266 users and $8,857 of revenue left in month 6. The no-decay projection claims $90,000 — a 28% overstatement in half a year.