Question: how to get calendar on iphone to sync with mac?
Answer: Method 1. (If you're using macOS Mojave or earlier, go to System Preferences, then click iCloud.) Uncheck the box of Calendars, then select Delete from Mac, your iCloud Calendar is turned off. A few minutes later, go to System Preference > iCloud, turn on iCloud Calendar and check if the calendars are synced to iPhone.