Churn Rate Calculator
Work out customer churn for any period and convert it properly between monthly and annual. Calculate revenue churn, NRR, GRR and negative churn from MRR movements, or paste a run of months to see the trend and a weighted average.
Enter your customers.
What this churn rate calculator does differently
Customer churn is customers lost divided by customers at the start, and every churn calculator does that sum. The mistakes happen around it: turning a monthly rate into an annual one by multiplying by 12, mixing rates calculated on different bases, quoting 1 / churn as a lifetime, and ignoring that losing customers and losing revenue are different things. This calculator does the sum and handles those.
| Omni | Martech Zone | This tool | |
|---|---|---|---|
| Customer churn rate | Yes | Yes | Yes |
| Monthly to annual, compounded | No | No | Yes, any period length |
| New customers during the period | No | For a growth target | Churn on start and on the average |
| Start, new and end, without a lost count | No | No | Yes |
| Revenue churn, NRR and GRR | No | No | Yes, with an MRR bridge |
| Negative churn | No | No | Yes |
| Month-by-month trend | No | No | Up to 120 periods, weighted average |
| Customer lifetime | 1 / churn | 1 / churn | 1 / churn, with its assumption stated |
| Export | Share result | None | CSV, Markdown, share link |
Pages as fetched on 3 November 2026.
How to calculate churn rate
Divide the customers lost during a period by the customers you had at the start of it. Start the month with 1,200 customers, lose 54, and churn is 54 / 1,200 = 4.5% for the month. If you only know the start and end counts and how many you signed, customers lost is start plus new minus end.
When many customers are added during the period, some companies divide by the average of the start and end counts instead. That gives a lower rate when you are growing. Neither is wrong, but rates on different bases cannot be compared, so the calculator shows both when you enter new customers.
Monthly and annual churn
Annual churn is not monthly churn times 12. A customer group that loses 4.5% each month keeps 95.5% of the remainder every month, so after a year it keeps 0.95512, about 57.5%, and annual churn is about 42.5%, not 54%. The difference grows as churn rises. The calculator converts between weekly, monthly, quarterly and annual rates by compounding, which assumes the rate stays the same through the year.
The same assumption sits behind the usual customer lifetime of 1 / monthly churn: 4.5% a month gives about 22 months. In practice newer customers tend to leave faster than long-standing ones, so treat the lifetime as a rough guide and check it against your own retention by cohort.
Revenue churn, NRR and negative churn
Revenue churn counts money rather than customers. Gross revenue churn is the recurring revenue lost to cancellations and downgrades, over the revenue at the start. Net revenue churn subtracts expansion, the upgrades and add-ons from customers who stayed. When expansion outweighs the losses, net revenue churn is below zero, which is called negative churn: the customers you started with pay more at the end than at the beginning.
Net revenue retention (NRR) is 100% minus net revenue churn, and gross revenue retention (GRR) is 100% minus gross revenue churn. New customers are left out of all four, because the measures describe what happens to existing revenue. The MRR bridge shows each movement from start to end, including new MRR, so you can see growth and retention side by side. For a full model of customer value, the LTV calculator takes churn and expansion as inputs.
Churn month by month
One month’s churn moves around, especially with a small customer base. Paste a run of months and the calculator gives each month’s rate, a chart, and an average weighted by the number of customers, so a small early month does not count as much as a large recent one. It also compares the first and second half of the run, and says when there are too few months to read a trend.
How to use this calculator
- Choose a modeCustomers, revenue, or a run of months.
- Set the periodA week, month, quarter or year; the results convert to monthly and annual.
- Enter the countsCustomers at the start and lost, or start, new and end; or MRR movements.
- Read the ratesChurn, retention, the annual equivalent and expected lifetime, or NRR and GRR.
- Check the trendPaste several months to see the weighted average and how it is changing.
- ExportCSV, a Markdown summary or a share link.