diff --git a/README.md b/README.md
index 6fef882..9d9d799 100644
--- a/README.md
+++ b/README.md
@@ -21,3 +21,8 @@ Built for my own use. Tested on the Nexus prod setup.
 
     pip install prometheus-api-client pyyaml rich
 
+
+## Burn rate
+
+The `burn_rate()` helper calculates how quickly you're spending your error budget
+relative to a 30-day window. A burn rate > 1 means you'll exhaust the budget before the window closes.