Churn Rate
The share of customers (or recurring revenue) you lose over a set period — the inverse of retention.
Churn rate % = (customers lost during period / customers at start of period) x 100Churn rate counts how many customers stop doing business with you over a chosen window — a month, a quarter, a year. You can measure it by logo (customers lost) or by dollars (revenue or MRR churn), and the two can point in opposite directions: lose ten small accounts and keep one whale, and your logo churn looks alarming while revenue churn barely moves.
The formula is customers lost during the period divided by customers you started with, times 100. Everything hinges on the choices around it: the length of the period, which cohort you count, and whether downgrades and failed renewals count as churn or something softer.
For a support team, churn is the metric everyone upstream points at you to explain. A hard interaction, a slow reply, an unresolved ticket — any of these can be the shove that sends an already-wavering customer out the door. But churn is a lagging, many-parented outcome; price, product gaps, a champion changing jobs, and a competitor's discount all pull on it too.
What it hides: aggregate churn blends voluntary departures with involuntary ones (expired cards, failed payments) that a billing fix would solve, and it lands weeks or months after the experience that triggered it — so it's a poor real-time signal for the desk. It also averages your healthiest and sickest cohorts into one flattering number, and "poor service" in an exit survey is a catch-all customers reach for when the real story was one bad incident on top of an existing reason to leave.