You can export your calendar as an iCal file if you need to migrate your events to another calendar. You can also import calendars to Google Calendar from iCal or CSV-files.
Exporting Google Calendar
- Open calendar's settings and click on the Import & export from the left side of the page
- Click on Export and a zip with all the calendars under My Calendars will be downloaded to zipped folder
- You can then extract the needed calendars from the zipped folder
Importing to Google Calendar
- Open calendar's settings and click on the Import & export from the left side of the page
- Click on the Select file from your computer and browse for the calendar file you want to import from your computer
- Select to which calendar you'd like to import the file by clicking the Add to calendar (default is your primary calendar)
- Click Import