Pulling an external calendar into Google Calendar, properly

If you have ever added a calendar with Google’s From URL option and then watched a cancelled meeting sit stubbornly on your grid for most of a day, you have met the problem this app exists to solve.

What an iCal feed actually is

An iCal feed is a plain text file at a URL, listing events in a standard format. Almost everything that keeps a schedule can publish one: booking systems, university timetables, project trackers, other calendar providers. The file is not a live connection. It is a document that someone rewrites when the underlying schedule changes, and your calendar client re-reads it whenever it decides to.

Why the built-in option feels broken

Google Calendar subscribes to the URL and re-reads it on its own schedule, which is neither published nor adjustable. In practice that means changes on the source can take hours to surface. For a read-only view of a public holiday calendar, fine. For anything you make decisions from — a client’s availability, a room booking, a shift rota — the lag is the whole problem. Worse, subscribed calendars are read-only, so you cannot correct or annotate an event on your side.

Syncing instead of subscribing

The alternative is to treat the feed as a source and write real events into a Google Calendar you own. That is what ICalSync does: it reads the feed, works out what changed, and creates, updates or removes the matching events in the destination calendar in realtime. Because the events are yours, they behave like everything else on your calendar — searchable, colour-coded, visible to the people you share with, available offline on your phone.

Rule of thumb: subscribe when you only need to look at a calendar, sync when you need to act on it.

Setting one up

1. Find the iCal (.ics) URL in the source system. It is usually under a share, publish or export menu.
2. Install ICalSync from the Google Workspace Marketplace and grant the calendar permissions.
3. Paste the URL, choose which of your calendars the events should land in, and save.
4. Check one event you know recently changed, to confirm the mapping looks the way you expect.

After that there is nothing to maintain. If the source moves a meeting, your calendar moves it too.