Churn is the share of customers, subscribers or contracts that stop within a period. It is the counterpart of retention: what leaks out the back door while you invest at the front.
This page explains how to calculate churn, which variants exist, what usually causes it and which measures genuinely help.
How to calculate churn
Customer churn = cancellations in the period / customers at the start of the period × 100.
Example: 400 customers at the start of the quarter, 24 cancel → 6% quarterly churn.
Revenue churn = revenue lost in the period / revenue at the start of the period × 100.
The two can differ sharply. Lose 2% of customers, but if your largest account is among them, revenue churn might be 15%. Always look at both. In subscription models, combine that with MRR/ARR and CLV.
| Variant | What it measures | Why it matters |
|---|---|---|
| Customer churn | Number of departing customers | Volume and satisfaction |
| Revenue churn | Revenue lost | Financial impact |
| Net revenue churn | Loss minus growth in existing customers | Whether you grow without new customers |
| Voluntary churn | The customer chooses to stop | Value and experience |
| Involuntary churn | Failed payment, expired card | Often easy to fix |
Don't overlook involuntary churn: failed payments are an operational problem, not a satisfaction problem, and usually the fastest fix available.
Where churn usually comes from
- No value experienced early. Most cancellations are decided long before they are submitted.
- Wrong expectations at the sale. What marketing promises and what the product does drift apart. See CX.
- The wrong customers acquired. Customers outside your ideal profile leave faster; see lead scoring.
- A change of contact person at the customer, removing your internal advocate.
- A price increase without visible value.
- A bad experience when something breaks. Not the fault but the recovery decides whether someone stays.
- Simply being forgotten. No contact, no usage, no reason to stay.
What actually helps
- Measure churn per cohort, not as one average. March customers behave differently from November's; the average hides that.
- Improve the first period. Make sure a new customer quickly achieves what they came for.
- Spot signals early. Declining usage, unanswered messages or falling engagement often precede a cancellation.
- Fix involuntary churn with payment retries and timely reminders on expiring details.
- Talk to leavers. One short exit question yields more than a survey of stayers.
- Select better up front. Fewer but better-fitting customers lowers churn without changing a single process.
Churn and your marketing maths
Churn decides how hard you must work for growth. At high churn, acquisition only fills the hole: your CAC stays the same while your CLV drops, so ad budget returns less. Reducing churn is therefore often cheaper than buying more traffic — and it affects everything downstream, see media mix.
Frequently asked questions about churn
How often should you measure churn?
Monthly or quarterly, depending on contract length. Always compare the same period length.
Does churn apply to online stores?
Yes, as repeat purchase behaviour: how many customers stop buying within a period that is normal for your product.
Can churn be eliminated?
No. Companies close, needs change. The goal is to manage churn, not to abolish it.
How is it different from retention?
Retention is the mirror image: the share of customers who stay. See customer retention.
Further reading
See customer retention, CX and CRM, or spar via /en/book-call.
Questions, or just want to spar?
We're happy to think along — call, email or drop by in the heart of Eindhoven.