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Cohort Retention Calculator

Enter a starting cohort size and how many customers remained each month after, get a full retention and churn breakdown plus an average monthly retention rate.

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Average monthly retention rate
0%

The steady monthly rate that would produce the same result over this period.

MonthRemainingRetentionChurnMonth over month

Enter your starting cohort size and each month's remaining customer count above, results update automatically.

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What cohort retention actually measures

Cohort retention tracks a single group of customers, everyone who signed up in the same month, for example, and follows what percentage of that specific group is still active in each month afterward. Unlike an overall churn rate, which blends customers of every age together, cohort retention isolates how a group of same-tenure customers behaves over time, which makes it far easier to spot whether a product change actually improved retention.

How the average monthly retention rate is calculated

Month-over-month retention divides each month's remaining customers by the prior month's count. The overall average monthly retention rate uses a geometric mean instead of a simple average, the constant monthly rate that, compounded over the full period, produces the same ending result as your actual data. That is the mathematically correct way to average a rate that compounds, a simple average of the individual monthly percentages would overstate retention.

What a healthy retention curve looks like

A healthy cohort curve drops in the first month or two, as customers who were never a good fit churn out, then flattens into a much shallower decline, sometimes called the retention curve reaching its floor. A curve that keeps declining steeply month after month with no flattening usually signals an ongoing product or onboarding problem rather than one-time early churn.

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FAQ

Cohort Retention Calculator: questions, answered

What is the difference between cohort retention and overall churn rate?
Overall churn rate looks at your entire customer base in a given period, mixing brand-new customers with five-year veterans. Cohort retention isolates one signup group and tracks only that group over time, which removes the noise of a growing or shrinking customer base and shows the true retention curve for customers of a given age.
Why use a geometric mean instead of just averaging the monthly percentages?
Retention compounds, each month's result depends on the month before it, so a simple average of individual monthly rates does not reconstruct the actual ending value. The geometric mean is the constant rate that, applied every month, would take you from the starting cohort size to the actual ending size, which is why it is the standard way to summarize a multi-period retention rate.
How many months of data can I enter?
As many as you have, enter your remaining-customer counts as a comma separated list in the order the months occurred, and the table and average will cover the full period you provide.
What counts as good retention for a SaaS product?
It varies widely by price point and market, but as a rough benchmark, consumer subscription products often see steep early drop-off with retention flattening somewhere in the 20 to 40 percent range by month 12, while B2B SaaS products with higher switching costs often retain 80 percent or more of a cohort at the same point.
Is my customer data uploaded anywhere?
No. All the calculations run locally in your browser using JavaScript, the numbers you enter are never sent to or stored on a server.

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