diff --git a/lego/apps/ical/constants.py b/lego/apps/ical/constants.py
index a6bd1e8d4..b6abae7ce 100644
--- a/lego/apps/ical/constants.py
+++ b/lego/apps/ical/constants.py
@@ -1,5 +1,5 @@
 HISTORY_BACKWARDS_IN_DAYS = 10
-REGISTRATION_EVENT_LENGTH_IN_MINUTES = 30
+REGISTRATION_EVENT_LENGTH_IN_MINUTES = 15
 
 TYPE_PERSONAL = "Personal"
 TYPE_EVENTS = "Events"