Customer retention curve month-by-month with LTV projection.
Inputs
Cohort retention curve
Month
Retention %
Active customers
Revenue (cumulative)
Summary
12-month LTV
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Cohort revenue
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Avg purchases per customer
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About this calculator
Cohort retention is the most diagnostic single view of ecommerce business health. Where conversion rate, AOV, and traffic measure the front of the funnel, cohort retention measures whether customers come back — which is the basis of all sustainable growth. Brands that can\'t retain at scale are renting growth via ads.
This calculator interpolates a full retention curve from 4 anchor points (months 1, 3, 6, 12). Industry-typical DTC consumer brands fit roughly: month 1 at 30-50%, month 3 at 20-30%, month 6 at 15-22%, month 12 at 10-15%. Premium brands run higher; commodity brands run lower. Subscription brands have completely different curves (more linear).
The lifetime revenue calculation extends the cohort projection to 12 months and shows total revenue per cohort. Compare that against your CAC to derive LTV:CAC. A cohort generating $260 of cumulative 12-month revenue at $80 CAC and 50% gross margin produces $130 lifetime contribution — LTV:CAC of 1.6×, which is below the 3× target most operators want.
Pair with the LTV:CAC Ratio Calculator (the absolute economics check) and the Repeat Purchase Rate calculator (single-rate companion to this curve view). Most operators discover their retention is weaker than they thought when they actually plot the curve.
Frequently asked questions
What is cohort retention?
Cohort retention measures what % of a group of customers (a cohort) is still active or still purchasing N months after their first purchase. A "30-day cohort" looking at month 6 retention shows what % of customers from that cohort bought again 6 months later.
What's a healthy retention curve?
Month 1: 30-50% repeat purchase. Month 3: 20-30%. Month 6: 15-22%. Month 12: 10-15%. These are DTC consumer averages — premium and subscription brands run higher; commodity dropshipping much lower. The shape (steep early drop, flat tail) is more important than absolute numbers.
How is this different from churn?
Churn is monthly subscription turnover — usually applied to recurring revenue. Cohort retention works for any ecommerce business, including non-subscription. Cohort retention shows the curve over time; churn is a single rate. Both measure the same underlying retention dynamic.
What if my month-1 retention is below 20%?
Two likely causes. First, low product-market fit (customers don't love the product enough to repeat). Second, broken post-purchase experience (no email follow-up, no flow to drive second purchase). The fix order: post-purchase email flow first, then product-market work if email doesn't lift.
How does retention impact LTV?
Massively. Each retention cohort produces revenue at decreasing rates over time. LTV = sum of (cohort revenue × retention curve). A cohort with 25% month-1 retention has roughly 2× the LTV of one with 12% month-1 retention even at identical AOV — because of the compounding effect on later months.