Fortunately, you have an easy way to set the default calendar in OS X and iOS. It lets you choose the default calendar for your event entries, and all of the future events will be added there.

Setting the Default Calendar in OS X

In OS X you can set the default calendar using the built-in Calendar app.

  1. Launch the Calendar app by clicking on Launchpad in your dock and searching for and clicking on Calendar.

  2. When the app launches, click on the “Calendar” menu followed by “Preferences…”

  3. When the panel opens, make sure you are inside the General tab. On the panel you should see a drop-down menu for “Default Calendar.” Click on it and you should be able to see all of your calendars. Now, click on the one that you wish to set as the default calendar on your machine and then exit out of the panel.

  4. Once you have set a calendar as the default, click on the plus icon in the app to create a new quick event to see if the default calendar has been properly set up. Enter some info in the event description box and then press Enter to add the event to the calendar.

  5. The event should have been added to the calendar that you selected as the default calendar. You can modify the event to be added to another calendar if you wish.

From now on any events that you create in the Calendar app will be added to your default calendar. This does not apply to the events created in the past, as they will remail the same. Here is how you can set the default calendar in iOS.

Setting the Default Calendar in iOS

  1. Tap on the Settings icon on your home screen.

  2. Tap on “Mail, Contacts, Calendars” on the following screen.

  3. Scroll all the way down, and you should see an option that says “Default Calendar.” Tap on it to select the default calendar for your device.

  4. You should be able to see all of the calendars you have on your device. Tap on the one you wish to set as the default.

  5. Head back to the previous screen, and you should see that the default calendar option now has the name of the calendar you just chose.

Both your Mac and iOS device now have your chosen calendars as their default calendars.

Conclusion

If you work around multiple calendars and wish to set one of those as the default, the above guide should help you do that.