Calendar file guides

What is an ICS file?

An ICS file is a plain-text calendar file in the iCalendar format. It can hold one event or a whole schedule so you can move dates and details between calendar apps, including Outlook, Google Calendar and Apple Calendar.

By Just Schedule Me · Sources checked on 1 October 2026

What does an ICS file contain?

A booking confirmation, a school timetable or an event website may give you a file ending in .ics. The format is called iCalendar, defined in RFC 5545. It is independent of a particular calendar service; it is not an Apple-only file.

Event details: Each VEVENT block describes an event. SUMMARY is its title; LOCATION and DESCRIPTION can add a place and notes. Optional organizer, attendee and alarm fields can describe people and reminders.
Dates and time zones: DTSTART marks the start, and DTEND can mark the end. A time ending in Z is UTC; TZID identifies a time zone. Times without either are “floating” local times. All-day events use dates rather than clock times, and their end date is exclusive.
Repeating events: RRULE can describe repetition, such as every week. Files may also carry exceptions or changed occurrences. One repeating event can therefore represent many dates.
Identifiers: UID identifies an event. DTSTAMP records a timestamp for the calendar entry, not the appointment's start time.

A small, original ICS example

This fictional file describes one practice event on 15 January 2030, from 14:00 to 15:00 UTC. The calendar wrapper surrounds a single event; the lines are instructions your calendar app reads.

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//JustScheduleMe//ICS explainer example//EN
BEGIN:VEVENT
UID:ics-explainer-20300115T140000@example.invalid
DTSTAMP:20261001T000000Z
DTSTART:20300115T140000Z
DTEND:20300115T150000Z
SUMMARY:Practice calendar event
LOCATION:Fictional library room
END:VEVENT
END:VCALENDAR

The digits in 20300115T140000Z mean 2030, January 15, at 14:00 UTC. Your calendar may display a different clock time in your local zone. This example has no guests, links or embedded alerts; your calendar's own notification defaults may still apply.

To try it, copy the example into the ICS viewer without adding anything to your calendar. Use the ICS file generator for a downloadable file with your own details.

How to open or import an ICS file

To inspect a file without creating events, open it in a plain-text editor or the ICS viewer. Our viewer reads the file in your browser. Importing into a calendar is a separate action.

Outlook: follow the Outlook ICS import guide for separate web, new Outlook and classic Windows steps. Account support differs.
Google Calendar: on a computer, use Settings → Import & export, choose the file and destination, then import. Our Google Calendar guide includes a practice download. See Google's import help.
Apple Calendar on Mac: use File → Import, choose the .ics file, then select the receiving calendar. See Apple's Mac import instructions.
iPhone: use the existing ICS to iPhone Calendar guide for files that open as text or have no Add option.

These vendor paths were checked against official help; we did not perform signed-in imports on those apps for this guide. After importing, check the destination and one event's time before adding the file again.

What an ICS file does not guarantee

A downloaded file is a snapshot. Later edits by the sender do not update an imported copy. To follow a changing schedule, subscribe to its published calendar feed URL instead. See the Outlook subscription steps.

Shared formatting does not mean every app preserves every detail. Google's import help says guests and conferencing data are not imported. Check recurrence and reminders in the destination rather than assuming they survived. Importing a saved copy is also not a substitute for responding to a meeting invitation in your calendar app.

If a file fails to import, use the ICS validator to find formatting issues. A pass does not prove that every calendar app will accept it. For a table of events, use ICS to CSV; a spreadsheet is useful for checking dates, but is not a live calendar subscription.

Handling files from other people

Check that you expected the file and recognize its sender. Preview event titles, dates and notes before importing; treat links in descriptions as you would links in an email. A valid file format does not establish who sent it.

Calendar exports can include private addresses, meeting links and attendee details. Do not post a real export publicly to get help. The viewer and validator work in your browser; choose a fictional example when sharing a problem with someone else.

Avoid subscribing to unfamiliar feeds: they can keep adding events. For unwanted Apple Calendar events or subscriptions, follow Apple's removal and unsubscribe guidance.

No ICS file yet?

If your schedule is in a spreadsheet, use the CSV to ICS converter to map columns and check the dates before exporting. To write an event by hand, use the ICS file generator.

For an email or pasted schedule, try text to calendar. For a flyer or screenshot, use photo to calendar. Just Schedule Me turns those details into events for you to review before exporting.

Paste or upload a schedule