Churn rate is the percentage of customers or revenue lost over a period. Customer churn counts lost accounts; revenue churn counts lost recurring revenue. High churn forces you to acquire customers to stay flat, making it one of the most damaging metrics to ignore.

Churn is the silent killer of growth math. Every point of churn is acquisition spend you must repeat to stand still. Reducing churn is almost always cheaper than acquiring replacements, and it compounds: lower churn raises LTV, which raises what you can afford to spend on acquisition. Fix the leak before scaling the inflow.

Example:

 You start the month with 200 customers and lose 6. Customer churn rate is 6 / 200 = 3% monthly.

What is the difference between customer churn and revenue churn?

 Customer churn counts the number of accounts lost. Revenue churn counts the recurring revenue lost, which can differ if larger or smaller customers leave.

Why is reducing churn so valuable?

 Lower churn raises customer lifetime value and reduces the number of new customers you must acquire to maintain revenue, improving every growth metric.