---
title: What is Churn rate?
url: https://markin.ai/glossary/churn-rate
category: Retention and churn
---

# Churn rate

> Churn rate is the share of customers, or of revenue, lost in a period. Customer churn counts people; revenue churn weights them by value. The two diverge whenever the customers leaving are systematically larger or smaller than average.

## How it is calculated

```
Churn rate = Customers lost in period / Customers at start of period
```

State the window and whether it is customer or revenue churn. Undefined churn rates are not comparable across teams.

## Why it matters for ARPU

Churn is the largest single drag on ARPU in most large B2C bases, and it is the input with the most leverage in any lifetime-value model.

## Related terms

- [Voluntary vs involuntary churn](https://markin.ai/glossary/voluntary-churn), Voluntary churn is a customer deciding to leave.
- [Churn prediction](https://markin.ai/glossary/churn-prediction), Churn prediction estimates the probability that a given customer will stop paying within a defined horizon, using behavioural, transactional and service signals.
- [Retention curve](https://markin.ai/glossary/retention-curve), A retention curve plots the share of a cohort still active against time since acquisition.
- [Gross revenue retention](https://markin.ai/glossary/gross-revenue-retention), Gross revenue retention measures how much starting cohort revenue survives a period counting only losses: churn and downgrades, never expansion.

## Go deeper

- [Customer churn prediction guide](https://markin.ai/blog/customer-churn-prediction-guide), The pillar guide to churn.
- [Churn economics in streaming and telecom](https://markin.ai/blog/churn-economics-streaming-telecom), What a point of churn is worth.

Source: https://markin.ai/glossary/churn-rate