With Google Calendar you can control who can see your calendars and events. When you make your calendar public, the events on that calendar are public as well meaning that people can search for it and find it in a variety of ways, including via Google Web search.
Share your calendar with everyone
To share your calendar with everybody, just follow these steps:
In the calendar list on the left, click on the down-arrow button next to the appropriate calendar, then select Share this calendar
Select Make this calendar public
If you don't want others to view the details of your events, select See only free/busy (hide details)
Allow colleagues to edit your calendar
- In the calendar list on the left, click on the down-arrow button next to the appropriate calendar, then select Share this calendar
- Enter the email address of the person you want to share the calendar with, select the proper permission setting to the right and click Add Person:
It is usually only required to set Make changes to events in order to give someone the access they need to manage your calendar. If you would like to delegate full control to your calendar, select Make changes AND manage sharing
Make a calendar private
In the calendar list on the left, click the down-arrow next to the calendar you'd prefer not to share with the public, then select Share this calendar.
Make sure the 'Make this calendar public' box is not checked.
Finally, when creating events, make sure that either 'default' or 'Private' is selected under Options >Privacy.
Changes in sharing permissions will generally take effect within a few minutes but, in some cases it may take up to 24 hours.