Churn calculator
The churn calculator takes one month of customers and MRR and gives you customer churn, what it compounds to over a year, revenue churn and net revenue retention.
Use it to see how much of each month's growth goes on replacing the customers who left.
Churn is the customers who cancelled over the customers at the start of the month, and a year compounds it rather than multiplying it by 12.
Built by the IndieHacked team
- 46.7% of customers gone in a yearAt this rate, compounded month by month
- 19 months average customer lifetime1 divided by monthly churn, a floor rather than a forecast
- 6% gross revenue churnCancellations and downgrades over starting MRR
- 96.2% net revenue retention this monthAbout 62.7% over a year if every month looks like this one
- $3,000 a year in lost MRRThis month's losses times 12, if nothing replaces them
Next to published data
- 6.1% median monthly churn where customers pay under $25 a monthPublic, ChartMogul, data Nov 2021 to Jan 2022
- Under 2% monthly churn puts a SaaS company in the top 25%Public, ChartMogul, data Nov 2021 to Jan 2022
- 82% median yearly net revenue retention, B2B SaaS with $250k ARR or morePublic, ChartMogul, 2025 data
How the numbers work
Customer churn
Monthly customer churn is the customers who cancelled during the month divided by the customers you had at its start, as a16z defines it in its 16 startup metrics (2015). Customers who joined during the month are not in the starting count, so leave them out of the cancellations too. Stripe's dashboard adds the month's new customers to the bottom of the division, so its rate reads lower for the same month.
A year compounds the monthly rate. At 5% a month, 95% of customers are left after one month and 95% of those after the next, so a year ends with 54% of them: 46% churn, not 60%.
The monthly benchmarks come from ChartMogul's customers, averaged over November 2021 to January 2022: a median of 6.1% where customers pay under $25 a month, 2.2% where they pay above $500, and under 2% for the top 25% (published 23 February 2022). They are the latest monthly figures we found published as text; ChartMogul's newer reports show their price bands in charts.
- Monthly customer churn
- customers who cancelled / customers at the start
- Customers gone in a year
- 1 - (1 - monthly churn)^12
- Average customer lifetime
- 1 / monthly churn
Revenue churn and retention
Gross revenue churn counts the MRR you lost, cancellations plus downgrades, over MRR at the start. Net revenue retention adds back what the customers who stayed added through upgrades. Above 100%, the upgrades outweighed everything you lost.
ChartMogul measured a median yearly net revenue retention of 82% for B2B SaaS companies with $250k ARR or more in 2025, with the upper quartile at 97% (report published 10 December 2025). That is a yearly figure, so the calculator compounds your month to a year before you compare, which assumes each month repeats this one.
- Gross revenue churn
- (MRR lost to cancellations + MRR lost to downgrades) / MRR at the start
- Net revenue retention
- (MRR at the start - losses + upgrades) / MRR at the start
- A year at this rate
- net revenue retention^12
Why the lifetime is a floor
1 divided by churn assumes each customer is as likely to leave as the next, month after month. Customers differ: the ones likely to leave go early, so a cohort churns less as it ages. Peter Fader and Bruce Hardie model this in their work on customer retention (2007 and 2010), and ChartMogul's 2026 LTV report found that by 36 months, cohorts had earned a median 14.4% more than a simple lifetime value predicted.
Use the lifetime to compare one month with another. Do not promise it to a buyer or an investor as a customer's value.
Questions founders ask
What is a good monthly churn rate?
It depends on what customers pay. ChartMogul's data from November 2021 to January 2022 put the median at 6.1% a month where customers pay under $25 a month and 2.2% where they pay above $500, and under 2% puts a SaaS company in the top 25%.
Why is yearly churn not monthly churn times 12?
Each month's churn applies to the customers who are left, not the ones you started with. 5% a month leaves 54% of customers after a year, so yearly churn is 46%, not 60%.
What is the difference between customer churn and revenue churn?
Customer churn counts people and revenue churn counts money. Losing ten $9 customers is not the same as losing one $500 customer. Downgrades never show in customer churn, but they cut revenue.
What is net revenue retention?
The share of a period's starting MRR still coming from those same customers at its end, upgrades included. ChartMogul's 2025 data put the yearly median at 82% for B2B SaaS with $250k ARR or more and 49% for B2C SaaS.
Why does my churn look higher here than in Stripe?
Stripe divides cancellations by the customers at the start of the 30 days plus the new customers who joined during them. This calculator divides by customers at the start, so the same month reads higher here. Compare months using the same formula.
Do failed payments count as churn?
Stripe counts a subscriber as churned once their subscriptions are cancelled or unpaid, so a card that keeps failing ends up in churn. Count those customers as lost here too, and win back the ones you can before the month closes.
Does a calculator work in euros, pounds or kronor?
Yes. The maths is the same in any currency and the dollar sign is a label. Enter every amount in the same currency.
Is anything I type into a calculator saved or sent anywhere?
No. A calculator runs in your browser and nothing you enter leaves it. Close the page and the numbers are gone.
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