Churn rate is a metric used in business to measure the rate at which customers are leaving or cancelling a service. It is usually expressed as a percentage of the total number of customers over a specific time period.
For example, if a company has 100 customers and 4 of them cancel their service in a given month, the churn rate for that month would be 4%. High churn rates can be an indication of poor customer satisfaction and can lead to decreased revenue and profitability for a company.