Open Google Calendar
Click the gear icon and select Settings
Go to Add calendar
Choose From URL or Import & export
Copy the Outlook calendar iCal link or export the Outlook calendar as an .ics file
If using a URL, paste the Outlook calendar link into Google Calendar and add it
If using a file, import the .ics file into Google Calendar
In Outlook, open Calendar settings
Publish or share the calendar and copy the ICS link if available
If you want two-way sync, use a third-party sync tool that supports Outlook and Google Calendar
Sign in to both accounts in the sync tool
Select the calendars to sync
Choose sync direction and settings
Save and start syncing
Check both calendars to confirm events are appearing correctly