diff --git a/src/services/license_service.py b/src/services/license_service.py
index 2e8070e..5c25238 100644
--- a/src/services/license_service.py
+++ b/src/services/license_service.py
@@ -468,7 +468,12 @@ async def _check_budget_warning(
     if available <= 0 or lic.get("budget_warning_sent"):
         return
 
-    threshold = lic.get("budget_warning_percent") or 80
+    # 0 schaltet die Warnung bewusst aus, NULL faellt auf die Voreinstellung 80.
+    threshold = lic.get("budget_warning_percent")
+    if threshold is None:
+        threshold = 80
+    if threshold <= 0:
+        return
     percent = (used / available) * 100
     if percent < threshold:
         return