Churn Rate Calculator
Customer churn, revenue churn and net revenue churn from one set of numbers. They routinely disagree — a business can shed customers and grow revenue in the same month — so quoting one without saying which is how churn conversations go wrong.
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There is no single churn rate. This churn rate calculator computes all three — customers, revenue, and revenue after expansion — because a business can be losing customers and growing revenue at the same time, and only one of those numbers gets quoted.
At the beginning of the period.
Cancelled during the period. New signups do not count.
Monthly recurring revenue at the beginning.
From cancellations and downgrades.
Upgrades from customers who stayed.
Customer churn is 3.0% and net revenue churn is -3.5% — negative, because $6,000 of expansion outweighs $2,500 of losses. The cohort is shrinking in headcount and growing in value. Quote the customer figure and you understate the business; quote only the net figure and you hide a retention problem.
Churn is usually a product problem wearing a metrics costume. If you are building the product largely on your own, Tekk turns what you want into specs your coding agent can actually execute.
Three rates, one period
customer churn = customers lost ÷ customers at the start
revenue churn = MRR lost ÷ MRR at the start
net revenue churn = (MRR lost − expansion MRR) ÷ MRR at the start
The denominator is always the start of the period. Customers acquired during it do not belong there, and putting them in is the most common way a churn rate comes out quietly too low.
Worked example
500 customers and $100,000 of MRR at the start. Fifteen customers leave, taking $2,500 with them. Customers who stayed upgrade by $6,000.
| Measure | Working | Result |
|---|---|---|
| Customer churn | 15 ÷ 500 | 3.0% |
| Revenue churn | $2,500 ÷ $100,000 | 2.5% |
| Net revenue churn | ($2,500 − $6,000) ÷ $100,000 | −3.5% |
| Net revenue retention | 1 − (−3.5%) | 103.5% |
Three per cent of customers gone, and the revenue base grew. Both statements are true, and which one you lead with is a decision rather than a fact.
Annualising: compound, do not multiply
| Monthly churn | × 12 | Compounded |
|---|---|---|
| 1% | 12.0% | 11.4% |
| 3% | 36.0% | 30.6% |
| 5% | 60.0% | 46.0% |
| 10% | 120.0% | 71.8% |
Multiplying counts customers churning twice. Someone who cancelled in February is not available to cancel again in March, so the correct form is:
annual churn = 1 − (1 − monthly churn) ^ 12
At 10% monthly the naive figure exceeds 100%, which should be the giveaway.
What the retention curve shows
Start a cohort at 100% and let it run for two years on the numbers above:
| Month | Customers left | Revenue from them |
|---|---|---|
| 0 | 100% | 100% |
| 12 | 69.4% | 151.1% |
| 24 | 48.1% | 228.3% |
The lines go in opposite directions. Two thirds of the original customers remain after a year and they are worth half again what the whole cohort was worth at the start.
This is what "negative churn" means in practice, and it is why enterprise SaaS businesses tolerate customer churn rates that would be alarming in consumer subscriptions — provided the accounts that stay keep growing.
Churn and lifetime value
average customer lifetime = 1 ÷ churn rate
At 3% monthly that is 33 months. At 6% it is 16.7. Halving churn does not improve lifetime value by a little — it doubles the lifetime, and lifetime value with it. Of all the levers in a SaaS model this is the one with the most leverage and the least glamour.
How it works
- 1
Enter the start of the period, not the end
Churn is a share of what you began with. Customers who signed up during the period do not belong in the denominator, and including them is the most common way a churn rate comes out flatteringly low.
- 2
Add the revenue lines
MRR at the start, MRR lost to cancellations and downgrades, and expansion from customers who stayed and spent more. Those three give you gross and net revenue churn, and the gap between them is what a customer churn rate calculator on its own cannot show.
- 3
Read all three, then pick one deliberately
The tool annualises by compounding rather than multiplying, plots what is left of the cohort over two years, and says plainly when net churn has gone negative. Which figure you report is a choice; making it accidentally is the problem.
Frequently asked questions
- How do you calculate churn rate?
- Divide the customers lost during a period by the customers you had at the start of it. A company that began the year with 200 customers and lost eight has a churn rate of 8 ÷ 200, or 4.0%. Churn and retention are the same fact stated two ways: retention is one minus churn.
- What is the difference between customer churn and revenue churn?
- Customer churn counts people; revenue churn counts money. Lose fifteen of five hundred customers and customer churn is 3.0%, but if those were your smallest accounts, revenue churn might be 2.5%. Lose one large account instead and the numbers invert. A churn rate calculator that reports only one of them is answering half the question.
- What is net revenue churn?
- Revenue churn after subtracting expansion from customers who stayed and upgraded. On the defaults above, $2,500 of losses against $6,000 of expansion gives net revenue churn of −3.5%. The negative sign is the good outcome: the cohort is worth more than it was despite having fewer people in it.
- Is negative churn actually possible?
- For revenue, yes, and it is the shape every SaaS investor looks for. For customers, no — you cannot lose fewer than zero. This is why the sign on a churn figure only makes sense once you know which churn is being quoted, and why a saas churn rate calculator should compute both.
- What is net revenue retention?
- One minus net revenue churn, expressed as a percentage. Net revenue churn of −3.5% is an NRR of 103.5%: every hundred dollars of recurring revenue became a hundred and three over the period without acquiring anyone. Above 100% is the threshold that matters; 120%+ is exceptional.
- How do I annualise a monthly churn rate?
- Compound it, do not multiply it. Three per cent monthly is 30.6% annually, not 36% — because a customer who churned in February is not available to churn again in March. Multiplying always overstates, and the error grows with the rate: 5% monthly is 46% a year, not 60%.
- What is a good rate for a saas churn rate calculator to show?
- It depends entirely on who you sell to, so a saas churn rate calculator can give you the number but not the verdict. Consumer subscriptions routinely run 5–7% monthly; SMB software often sits at 3–5%; enterprise contracts are usually measured annually and anything above 10% a year invites questions. Compare against your own segment or not at all.
- How does churn relate to customer lifetime?
- The churn rate calculator above reports it: average lifetime is one divided by the churn rate. At 3% monthly the average customer stays about 33 months. That figure feeds directly into lifetime value, which is why a small change in churn moves LTV so much — halving churn doubles the lifetime.
- Should I count downgrades as churn?
- In revenue churn, yes — a customer halving their plan has taken revenue out just as surely as one who left. In customer churn, no, because they are still a customer. This is a large part of why a customer churn rate calculator and a revenue one disagree, and an annual churn rate calculator that ignores downgrades will understate the revenue picture.
- What period should I measure over?
- Monthly for anything billed monthly, annually for annual contracts. Mixing them produces nonsense: a 3% monthly rate and a 3% annual rate describe wildly different businesses. If you must convert, compound rather than multiply, which is what the annualised figure above does.
- Why does the retention chart show revenue going up?
- Because when net revenue churn is negative, the cohort grows in value even as it shrinks in headcount. On the defaults, after twelve months 69% of the customers remain and they are worth 151% of the original revenue. Two lines going opposite directions is the whole argument for measuring both.
- Do you store the numbers I enter?
- No. The calculation runs entirely in your browser. Nothing is sent to a server, nothing is logged, and there is no account. Disconnect from the internet and it will still work.
- Why is this free, and what is Tekk?
- Tekk is a spec-driven development platform for people building software with AI coding agents. This calculator costs us nothing to run, and churn is usually a product problem wearing a metrics costume — which is a problem we work on. No signup, no run limit, no upsell inside the tool.
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