diff --git a/_data/rules.yml b/_data/rules.yml
index d0eff70..65a5ef7 100644
--- a/_data/rules.yml
+++ b/_data/rules.yml
@@ -1071,7 +1071,7 @@ groups:
             rules:
               - name: JVM memory filling up
                 description: JVM memory is filling up (> 80%)
-                query: 'sum by (instance)(jvm_memory_used_bytes{area="heap"}) / sum by (instance)(jvm_memory_max_bytes{area="heap"}) * 100 > 80'
+                query: '(sum by (instance)(jvm_memory_used_bytes{area="heap"}) / sum by (instance)(jvm_memory_max_bytes{area="heap"})) * 100 > 80'
                 severity: warning
 
       - name: Sidekiq