diff --git a/app.py b/app.py
index ef87529..a5e8bb4 100644
--- a/app.py
+++ b/app.py
@@ -187,6 +187,12 @@ def habit_create():
     if unit not in ['Tag', 'Woche', 'Monat', 'Jahr']:
         errors['unit'] = 'Die Einheit ist ungültig.'
 
+    # check if list_id is an int
+    try:
+        list_id = int(list_id)
+    except ValueError:
+        errors['list_query'] = 'Die Anzahl muss eine Zahl sein.'
+
     if errors:
         return render_template(
             'habit.html',
@@ -212,7 +218,7 @@ def habit_create():
         unit = 1
 
     # Save habit to database
-    habit = Habit.create(current_user.id, name, times, note, unit)
+    habit = Habit.create(list_id, name, times, note, unit)
 
     # Back to index
     return redirect(url_for('index'))