Understanding Calendar Sync

OneCal Calendar Sync allows users to synchronize multiple iCloud, Outlook or Google Calendars in real-time, automatically.

Grainy Texture — Illustration of synced Google Calendar with an Outlook Calendar.

Calendar Sync Illustration — Illustration of synced Google Calendar with an Outlook Calendar.

Good To Know

You do NOT need to set up Calendar Sync in order to use OneCal's Booking Links or Unified Calendar View features.

Supported Providers

Google Calendar
Microsoft Outlook
iCloud Calendar

Good To Know

OneCal is approved by Google and Microsoft and uses Official APIs to access your calendars. We act as a proxy and don't store or analyze any of the calendar data or events.

Sync Directions

OneCal supports one-way and multi-way calendar syncs.

One-Way Sync Direction

The one-way calendar sync allows you to sync one calendar to another, or to multiple calendars. The calendar sync would look like this:

Calendar A -> Calendar B
Calendar A -> Calendar B, Calendar C, Calendar D (and more calendars...)

Here is what the UI looks like:

Choose Source Calendar and Target Calendar(s)

Example 1:

You have a work calendar and a personal calendar. You can:

Create a one-way sync to sync Personal -> Work, by removing all event information, and just blocking the time in your Work calendar for personal events.
Create another one-way sync to sync Work -> Personal, by sending all event information to your personal calendar.

Example 2:

You have two work calendars and a personal calendar. You can:

Create a one-way sync to sync Personal -> Work1, Work2, by removing all event information, and just blocking the time in your Work calendars for personal events.
Create a one-way sync to sync Work1 -> Personal, by sending all Work1 information to your personal calendar.
Create a one-way sync to sync Work2 -> Personal, by sending all Work2 information to your personal calendar.

This configuration allows you to block time on your work calendars for personal events, and block time on your personal calendar for work events.

Your privacy is intact when blocking time on your work calendars for personal events, as all event details are stripped.

Multi-Way Sync Direction

The multi-way calendar sync allows you to sync multiple calendars under the same sync configuration.

Here is what the UI looks like:

Example:

You have 3 work calendars and a personal calendar. You want to sync all calendars by showing 'Busy' for clone events. You could create a multi-way calendar sync and select the calendars you want to sync. OneCal handles the rest.

One Sync per Calendar Pair

We strongly recommend syncing each calendar pair, in the same direction, with only one calendar sync. If you select a pair that is already synced by another calendar sync, OneCal warns you that this can result in multiple clone events for the same original event, and shows you which calendar sync already covers that pair.

This only concerns syncs covering the same pair in the same direction. Syncs in opposite directions, like Work -> Personal and Personal -> Work, are safe to combine: OneCal never clones its own clone events, so events cannot bounce back and forth between your calendars. See Does OneCal clone its own clone events?.

Sync Configuration

Both One-way and Multi-way calendar syncs have the same sync configuration.

Sync Configuration Settings

Sync Event Titles: Include original event titles in clone events, or choose to completely hide the titles and show a custom message.
Sync Event Description: Include a description from the original events.
Sync Event Participants: Include participants from the original events. Participants will be included in the event's description to prevent them from getting an invitation to the clone event.
Sync Event Location: Include physical location from original events.
Sync Event Conference Data: Include conference meeting links from the original events.
Mark Clones As Private: Clone events will be marked as private to other people in your organization.
Disable Reminders for Clones: Disable reminder notifications for clone events, so you don't get multiple notifications for the same event across multiple calendars.
Add an Identifier to Clone Events: The Identifier is appended to clone event titles to help you distinguish clone events from original events. If you choose to hide the event names, the Identifier appears as the title of your clone events.
Clone Events Colors: Choose to give clone events a custom color so you can easily distinguish them from original events in your calendar.
Sync Events by RSVP Response: Only events containing one of the selected responses will be synchronized.
Exclude Events By Color: Events colored with the selected color won't be synchronized.
Sync Free Events: Events marked as free will be synchronized.

How Often Do the Syncs Run?

The Calendar Sync is automatic. For Google and Outlook calendars it is real-time: as soon as a change happens in your source calendar(s), OneCal syncs all the target calendars. Changes on iCloud calendars are detected about every 10 minutes, since Apple does not provide a real-time API.