Who can see your calendars

By default a calendar is visible to exactly one person: you.

Sharing creates an unlisted link: anyone holding the link can view, but the page is excluded from search engines and the URL is unguessable.

Invited people see the calendar under their own account, as a viewer or an editor depending on the role you gave them. Viewers can only look; editors can also add and change events.

Individual events can be narrowed further: any event can be limited to you plus a few of the people on the calendar, and everyone else sees nothing there. See sharing one event with only some people.

You can refresh or revoke any share link at any time from the Share window, which cuts off everyone holding the old URL.