I could not imagine life without not Google Calendar, I rely on it for all my appointments and important schedule tasks
There could be many reasons why you would want to move your calendar to another Google account. You may want to move from a free Gmail account to Google Apps account where you use your own domain or maybe you are changing from one Google Apps account to another Google Apps account.
Youl could share your old account calendar with your new account. This is fine but please be aware if you delete your old account (or calendar) it will disappear forever so not really recommended unless you are sure you will never delete the old account.
Google offers many ways to get data out of their services and if you have not already you should head over to Google Takeout ow and download all your data for fun and peace of mind.
To transfer from one Google calendar:
1. Login to your old account and open your calendar
2. Click the down arrow next to the link you want to export (transfer)
3. From the settings page select the ICAL green button
4. Click the link in the box that opens (see image below)
5. This will download a file normally called basics.ics (this is your calendar in icalander format)
6. Login to your new Google Account where you want to transfer your calendar and open the calendar app
4. Click the down arrow alongside other calendars and select Import Calendar
5. Now select the basic.ics file you downloaded earlier and pick the calendar you want to add it to.
For Google Support Documents see: