diff --git a/geruecht/controller/userController.py b/geruecht/controller/userController.py
index 1a07598..63ce79b 100644
--- a/geruecht/controller/userController.py
+++ b/geruecht/controller/userController.py
@@ -212,13 +212,16 @@ class UserController(metaclass=Singleton):
             1 if oldMonth else now.month
         endDay = 1
         debug.debug("calculate end day of month")
+        lockedYear = lockedYear if lockedMonth != 12 else (lockedYear + 1)
+        lockedMonth = (lockedMonth + 1) if lockedMonth != 12 else 1
         for i in range(1, 8):
-            nextMonth = datetime(lockedYear, lockedMonth + 1, i)
+            nextMonth = datetime(lockedYear, lockedMonth, i)
             if nextMonth.weekday() == 2:
                 endDay = i
                 break
 
-        monthLockedEndDate = datetime(lockedYear, lockedMonth + 1, endDay)
+        monthLockedEndDate = datetime(
+            lockedYear, lockedMonth, endDay) - timedelta(1)
         debug.debug("get lock day from database")
         retVal = db.getLockedDay(date.date())
         if not retVal: