diff --git a/src/booking.py b/src/booking.py
index f7daedc..6cd2b89 100644
--- a/src/booking.py
+++ b/src/booking.py
@@ -176,6 +176,9 @@ class Event(models.Model):
             self.created = datetime.now(tz=timezone.get_current_timezone())
         self.ics = self.create_ics()
 
+        # Round down to the nearest minute to avoid collisions between events
+        self.end = self.end.replace(second=0, microsecond=0)
+
         # Send the event to the CalDAV server if it has not been cancelled yet
         if not self.cancelled:
             try: