Go to calendar.google.com and log in. Then go to the settings icon (gear icon) on the top right corner, and click on “Settings”.
In the Settings, click on the “Calendars” tab, and then “Edit Shared Settings” on the calendar you want to share.
Under “Share with Specific People”, enter the email address of the person you want the calendar shared to. Then under “Permission Settings”, choose the type of permissions for the person you’re sharing the calendar to. Then click on “Add Person”, the click “Save”.