Churn Rate Calculator
Enter how many customers you had at the start of the period and how many cancelled during it. Add starting and lost monthly revenue to get revenue churn as well. Nothing is sent anywhere.
In one sentence: Churn is the share of customers (or recurring revenue) at the start of a period that is gone by the end of it.
Formula: customer churn = lost ÷ start × 100; revenue churn = MRR lost ÷ MRR at start × 100; annualised = (1 − (1 − monthly churn)^12) × 100.
Customer churn and revenue churn are different numbers
Customer churn counts heads: 15 of 500 customers leaving is 3%. Revenue churn weighs them by what they paid: if those 15 were on the cheapest plan, revenue churn is lower than 3%; if they were the biggest accounts, it is higher. Both matter. Customer churn tells you how well the product retains people; revenue churn tells you what it costs. Quote which one you mean and over what period, because the same business can honestly report 3% monthly customer churn and 30% annual churn.
Why annualised churn is not twelve times monthly churn
Losing 3% a month compounds. After twelve months, 0.97 to the power of twelve, about 69%, of the starting customers remain, so the annual loss is about 31%, not 36%. The calculator applies this compounding. If your input period is already a year, read the first result as annual churn and ignore the annualised line.
Reading the result
Churn is the denominator of customer lifetime value: at 3% monthly churn an average customer stays about 33 months, at 6% about 17. Small changes in churn move lifetime value and the affordable acquisition cost a lot, which is why retention work usually pays better than more marketing once a product has traction. Pair this number with net revenue retention, which also counts upgrades and downgrades from the customers who stayed.
Frequently asked questions
Do customers who joined and left in the same month count?
Convention is to count only customers present at the start of the period in the denominator, and only those of them who left in the numerator. Treat same-month joiners and leavers as a separate conversion problem.
What is a good churn rate?
It depends on the market and price point; the useful comparison is your own rate over time and against the gross margin you need to recover acquisition costs.
Is my data stored?
No. Everything runs in your browser.