iOS 27 brings significant updates to Apple's Calendar app, introducing natural language input for events and reminders. Apple calls this 'Smart Event Details,' powered by Apple Intelligence. Users can now type events in their own words, and Apple Intelligence automatically fills in the title, time, location, and invitees. This feature works for both events and reminders, with an option to toggle it off in Settings for those who prefer manual entry.

The Calendar app also receives design updates in two main areas: event details view and event creation/editing. Tapping an event now opens a card overlay with a refreshed design, featuring reorganized options with icons. Event creation and editing screens have similarly been updated with the new visual style.

A notable addition is the Show as Busy/Free option for iCloud calendars, which was previously missing. This feature aligns iCloud calendar functionality with Google and other third-party calendar providers, allowing users to mark themselves as busy or free for iCloud events.

iOS 27 also introduces extra-large widgets for Home Screen and Today views, with Calendar supporting 'List' and 'Up Next' widgets in this new size. These larger widgets display more events and reminders, particularly useful on the iPhone Ultra's expanded display. Siri AI upgrades enhance calendar management with improved onscreen awareness and personal context understanding, plus a new visual intelligence button for scanning event flyers directly into calendar events.