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Churn & Retention Calculator

Enter your current customers, monthly churn rate and revenue. You get customers lost, revenue lost, expected customer lifetime and lifetime value.

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Short answer

Churn & Retention Calculator: what it does

Churn is the percentage of customers who leave each month. It looks small until you multiply it by your revenue — then it shows what you actually lose to people who cancel. A 5% monthly churn means half your customers leave every year.

Last updated 3 August 2026

Worked example

Here's one we ran earlier.

500 customers · 5% monthly churn · £14,500 MRR · £29 ARPU

Customers lost per month — 25
Monthly churn
5% of 500 customers. That's 300 customers over a year if you don't fix it — more than half your current base.
Annual churn — 46%
Compounded
What 5% monthly churn compounds to over twelve months. This is why monthly churn always looks smaller than it feels.
Revenue lost per month — £725
Money lost
25 customers × £29 ARPU. That's £8,700 a year walking out the door — often more than a founder's salary.

How it works

Three steps, no account.

Step 1

Measure churn monthly, not annually

A 5% monthly churn compounds to 46% annual churn. Annual numbers hide the leak and make it feel smaller than it is.

Step 2

Convert churn into revenue lost

Knowing you lost 25 customers is abstract. Knowing you lost £725 a month makes the cost of fixing retention obvious.

Step 3

Compare lifetime value to acquisition cost

If your LTV is low and your churn is high, every new customer is an expensive temporary visitor. Fix the leak before you pour more into acquisition.

Questions

Common questions.

What is a good monthly churn rate?

For small subscription businesses, 3–5% is common, 2% is good, and under 1.5% is excellent. For annual plans, measure revenue churn as well as customer churn.

What's the difference between customer churn and revenue churn?

Customer churn counts the number of customers who leave. Revenue churn counts the money they took with them. A few high-value customers leaving can cost more than many low-value customers.

How do I reduce churn?

Fix the first 30 days, since most churn happens early. Make onboarding specific, respond to support quickly, and reach out to customers who stop using the product before they cancel.

Is negative churn possible?

Yes. It happens when existing customers upgrade or buy more over time, so revenue from existing customers grows even if some leave. It's the sign of a healthy product.