Just as you probably want the same contacts and email messages on each of your devices (see Sync Contacts across Devices and Sync Email across Devices), you probably want to see the same calendars and reminders no matter which device you’re using.
Once again, services such as iCloud, Google Contacts, and Exchange can accomplish this readily with updates delivered via push or scheduled updates, and generally require only that each device be set up correctly.
Sync Calendars on a Mac
Go to System Preferences > Internet Accounts.
If the account you want to use for syncing calendars (iCloud, Exchange, Google, or CalDAV) is not already listed, click the account type on the right and follow the prompts to add it.
Select the account in the list on the left.
Make sure that the Calendars checkbox is selected ①.
① Make sure Calendars is selected to sync calendars from a cloud service such as iCloud with Calendar on your Mac.
Your calendars from the selected cloud service should now begin syncing with your Mac. However, not all calendar services support push syncing, and even when they do, you may prefer scheduled syncing. To check or change the sync interval:
Open the Calendar app, and go to Calendar > Preferences > Accounts > Account Name > Account Information.
Choose Push (if available) or a time interval from the Refresh Calendars pop-up menu.
Sync Calendars in iOS
Tap Settings > Mail, Contacts, Calendars.
If the account you want to use for syncing calendars (iCloud, Exchange, Google, or CalDAV) is not already listed at the top, tap Add Account and follow the prompts to add it.
Tap the account name and make sure Calendars is turned on for that account.
Your calendars from the selected cloud service should now be syncing with your iOS device.
