Churn Rate Calculator
Divide the customers who left during the month by the customers you had at the start of it. Lose 42 out of 1,200 and churn is 3.5%, leaving 1,158. Invert that 3.5% and you get the average lifetime: 100 ÷ 3.5 is 28.6 months. It holds only if churn stays level month after month, and that month count is what gets multiplied in a lifetime-value calculation.
Your numbers
Monthly churn
3.5%
Average lifetime
28.6mo
Customers left
1,158
Formula
Monthly churn = Customers lost ÷ Customers at start × 100, Average lifetime = 100 ÷ Monthly churn
The denominator has to be the customers you started the month with. Fold this month's new signups into it and a fast-growing company reports churn lower than it is. Customer churn and revenue churn are different numbers — if only the cheapest plans leave, 3.5% of people can be 1% of revenue. For the 12-month compounded figure, use the retention-rate page.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Customers at startCustomers you had at the start of the month; this month's signups are out. | 1,200 | 0 and up |
| Customers lostCustomers who left during the month; a headcount, not a revenue figure. | 42 | 0 and up |
Step by step
Quick reference table
Results when only Customers at start changes and everything else stays put.
| Customers at start | Monthly churn (%) | Average lifetime (mo) | Customers left |
|---|---|---|---|
| 600 | 7 | 14.3 | 558 |
| 900 | 4.67 | 21.4 | 858 |
| 1,200 | 3.5 | 28.6 | 1,158 |
| 1,800 | 2.33 | 42.9 | 1,758 |
| 2,400 | 1.75 | 57.1 | 2,358 |
What each result means
| Result | At default values |
|---|---|
| Monthly churn (%)The share of starting customers who left; inverted, it gives the average lifetime. | 3.5 |
| Average lifetime (mo)Average lifetime if churn holds level — 100 divided by the churn rate. | 28.6 |
| Customers leftCustomers still on the books when the month ends. | 1,158 |
Common mistakes
The denominator has to be the customers you started the month with. Fold this month's new signups into it and a fast-growing company reports churn lower than it is. Customer churn and revenue churn are different numbers — if only the cheapest plans leave, 3.5% of people can be 1% of revenue. For the 12-month compounded figure, use the retention-rate page.
Glossary
- Customers at start
- Customers you had at the start of the month; this month's signups are out.
- Customers lost
- Customers who left during the month; a headcount, not a revenue figure.
- Monthly churn
- The share of starting customers who left; inverted, it gives the average lifetime.
- Average lifetime
- Average lifetime if churn holds level — 100 divided by the churn rate.
- Customers left
- Customers still on the books when the month ends.
Frequently asked questions
Q. How is Churn Rate Calculator calculated?
Monthly churn = Customers lost ÷ Customers at start × 100, Average lifetime = 100 ÷ Monthly churn — Divide the customers who left during the month by the customers you had at the start of it. Lose 42 out of 1,200 and churn is 3.5%, leaving 1,158. Invert that 3.5% and you get the average lifetime: 100 ÷ 3.5 is 28.6 months. It holds only if churn stays level month after month, and that month count is what gets multiplied in a lifetime-value calculation.
Q. Can you walk through an example?
With Customers at start 1,200, Customers lost 42, the answer is Monthly churn 3.5%.
Q. What do I need to enter?
Enter Customers at start, Customers lost. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Customers at start moves the answer to Customers at start 600 → Monthly churn (%) 7 and Customers at start 2,400 → Monthly churn (%) 1.75. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
The denominator has to be the customers you started the month with. Fold this month's new signups into it and a fast-growing company reports churn lower than it is. Customer churn and revenue churn are different numbers — if only the cheapest plans leave, 3.5% of people can be 1% of revenue. For the 12-month compounded figure, use the retention-rate page.
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