How often do calendars sync?
It depends on the type of source calendar. Google Calendar and Outlook sources sync in real time; iCloud and .ics URL sources sync every 5 to 10 minutes.
How often does Google Calendar sync? It depends on which calendar is the source of the sync connection, not on which one is the destination.
Google & Outlook source calendars — real time
Sync connections where the source calendar is a Google or Outlook calendar are “real-time” and work based on push notifications rather than syncing at periodic intervals. Google Calendar and Microsoft tell CalendarBridge the moment an event changes, so the change typically propagates to the destination calendar within a minute — but can take longer depending on factors such as network conditions and the number of events on a calendar.
This applies in both directions. A Google source syncing to an Outlook destination, or an Outlook source syncing to Google, is real-time either way. There is no polling interval to configure and no way to make it faster.
iCloud & Internet source calendars — every 5–10 minutes
Sync connections where the source calendar is an iCloud or Internet (.ics URL) calendar sync every 5 to 10 minutes. Apple does not provide a real-time API that third parties can use, and .ics feeds have no notification mechanism at all, so both are checked on a schedule instead.
How often does Google Calendar update subscribed (.ics URL) calendars?
This is a different question, and it catches people out. If you subscribe to an .ics URL inside Google Calendar using Other calendars → From URL, the refresh is handled by Google, not by CalendarBridge. Google refreshes those subscriptions on its own schedule — commonly many hours — and there is no setting that makes it faster.
Syncing the same .ics URL with CalendarBridge instead checks it every 5 to 10 minutes and writes real events onto the destination calendar, so they behave like normal events and count toward your availability. See how to get an .ics URL for your calendar.
Making a sync run now
You do not normally need to. If a calendar looks out of date beyond the intervals above, you can resync the sync connection, which rebuilds the event copies from scratch.
If events are consistently late or missing, start with troubleshooting calendar syncing.