diff --git a/src/components/event-modal.tsx b/src/components/event-modal.tsx
index d82a0c1..cb2db62 100644
--- a/src/components/event-modal.tsx
+++ b/src/components/event-modal.tsx
@@ -328,7 +328,8 @@ export function EventModal({ type, babyId, onClose, onSaved, initialEvent }: Pro
     let resolvedEndedAt = form.endedAt;
     if (config.hasDuration && !resolvedEndedAt && config.defaultDurationMin) {
       const start = new Date(form.startedAt);
-      resolvedEndedAt = new Date(start.getTime() + config.defaultDurationMin * 60000).toISOString().slice(0, 16);
+      const end = new Date(start.getTime() + config.defaultDurationMin * 60000);
+      resolvedEndedAt = new Date(end.getTime() - end.getTimezoneOffset() * 60000).toISOString().slice(0, 16);
     }
 
     localStorage.removeItem(TIMER_KEY);