Calculate monthly and annual customer churn rate, revenue churn, and the impact on customer lifetime value. Essential for subscription businesses and SaaS companies.
One month of customers, and one month of revenue
Customers over the month
Total active customers at the beginning of the month.
Customers who cancelled or did not renew during the period.
Recurring revenue over the same month
$
Total MRR at the start of the period. Used for revenue churn.
Approximate share of customers still active and the implied count at your monthly churn rate, starting from the customers you entered.
Month
Retained %
Customers remaining
0
100.0%
1,000
3
85.7%
857
6
73.5%
735
12
54.0%
540
24
29.2%
292
36
15.8%
158
Estimates only — not financial, tax, or professional advice.
100% private — every number you enter is calculated in your browser and never sent to our servers.
What it calculates: Monthly Churn Rate, Annual Churn Rate, Monthly Revenue Churn, Implied Customer Lifespan.
Updated 5 June 2026 · Transparent assumptions
Losing 5% a month is 45.96% a year, not 60%, because you cannot lose the same customer twice
Multiplying monthly churn by twelve is the most common error in subscription reporting. At 5% a month you keep 95% of customers each month, so after a year you retain 0.95 to the twelfth power — 54.04% — and have lost 45.96%. The naive 60% figure would have you losing more customers than you ever had.
The gap widens as churn rises. At 10% monthly the compounded annual figure is 71.8%, not 120%, which is impossible. Any report showing annual churn above 100% is multiplying rather than compounding, and the same mistake in reverse understates how long customers actually stay.
A 5% monthly loss rate means the average customer stays 20 months
If a constant fraction of customers leaves each month, the average lifetime is the reciprocal of that fraction: one divided by 0.05 is 20 months. That single number is what makes churn actionable, because it converts a percentage into the horizon over which a customer has to repay what they cost to acquire.
It is also brutally sensitive. Cutting churn from 5% to 4% lifts average lifetime from 20 months to 25 — a quarter more revenue per customer, with no change to acquisition at all. Halving churn to 2.5% doubles lifetime to 40 months. This is why retention work usually returns more than the same effort spent on acquisition.
Both read 5% here, and when they diverge the gap is the whole story
Customer churn counts accounts lost; revenue churn counts the recurring revenue lost with them. In the default month both are 5%, which means the customers who left were worth exactly the average. That is the uninteresting case.
The interesting cases are the divergences. Revenue churn well above customer churn means your larger accounts are leaving — the most dangerous pattern in a subscription business, and one that customer counts alone will hide. Revenue churn below customer churn means you are losing small accounts while keeping big ones, which is survivable and sometimes deliberate.
Neither figure here counts expansion. A business whose remaining customers upgrade can have positive net revenue retention — more revenue from the existing base than it started with — even while losing accounts every month. That is the metric investors ask for, and it needs upgrade revenue this calculator does not take.
New customers leave far faster than established ones, and one blended rate hides it
Churn is rarely uniform. Most subscription businesses lose a large share of customers in the first ninety days and then churn far more slowly among those who remain. A single blended rate averages those two very different populations and produces a number that describes neither.
The consequence is that average lifetime computed from a blended rate overstates how long a new customer stays and understates how long a two-year customer will. Cohort analysis — tracking each month\u2019s signups separately — is the fix, and this calculator is best used on a single cohort or on a mature base rather than on everything at once.
One month, no seasonality, and no distinction between voluntary and involuntary loss
A single month is a noisy sample, especially for a business with fewer than a few hundred customers, where two or three cancellations move the rate by a point. Annual contracts concentrate churn into renewal months, so a monthly figure taken outside that window will read artificially low.
The calculation also does not separate voluntary churn from involuntary — customers who chose to leave against those whose card simply failed. Involuntary churn is often a fifth of the total and is far cheaper to fix, through card-retry logic and expiry reminders, than any product change. Splitting the two is usually the first useful thing a business does with this number.
Sources & References
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
Results are estimates for planning and analysis based on the figures you enter. They are not accounting, tax, or financial advice — verify with your own records and a qualified professional before making decisions.
Published the calculator with its formula, worked example, assumptions, limitations and a bespoke guide, and added an automated formula test suite covering it.
Property-tested that annual churn compounds rather than multiplying — 5% a month is 45.96% a year, not 60% — and that implied customer lifetime is the reciprocal of the monthly rate.
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