Calendar Sync Utility · Effective October 16, 2026
Calendar Sync Utility is a macOS application that copies the signed-in user's own Google Calendar events into a calendar the user selects in Apple Calendar on their own Mac, so their schedule is visible in one place. Optionally, it writes to a Google calendar the user owns: copies of the user's events, or "busy" holds for times the user is busy on another of their calendars. It is distributed directly by its developer.
With the account holder's explicit OAuth consent, the application reads
Google Calendar data — event titles, descriptions, locations, dates and
times, and whether each event shows as busy — using read-only access
(calendar.readonly), along with the account's email address,
which is used only to display which account is signed in.
Only when the user chooses a Google calendar as a destination does the
application request, in a separate consent, access to events on the
calendars the user owns (calendar.events.owned). It uses
that access only to create, update and delete the events it wrote there
itself, each marked as its own in the event's private extended
properties and description; it never changes events the user or anyone
else made, and sends no invitations or update emails.
Calendar data is used for exactly one purpose: copying the user's own events, or holds for the times they occupy, into calendars the user selects, in Apple Calendar on the user's own computer or in the user's own Google Calendar. There is no other processing, no profiling, and no use of the data for advertising of any kind.
Everything stays on the user's own device. Sign-in tokens are stored in the macOS Keychain; event data is written only into the calendars the user chose. The application has no server component, and the developer has no access to any data belonging to other users.
No data is sold, shared, or transferred to any third party. Calendar data leaves the device only insofar as the user's chosen Apple calendar syncs through the user's own Apple iCloud account, under Apple's terms, or is written to the user's own Google calendar at the user's direction.
This application's use of information received from Google APIs adheres to the Google API Services User Data Policy, including the Limited Use requirements.
Access can be revoked at any time from the user's Google Account permissions page or by signing out inside the application. Removing a mapping inside the application deletes the events it wrote. Removing the application and deleting the copied calendar removes all locally stored data.