iPhone Calendar Not Syncing? Here Are 16 Easy Fixes for You!

2023-05-11 00:00:00/Posted by Alleny Gavinto iOS Transfer Topic/Follow @ MobiKin

You may keep daily schedules, meetings, and other events on iPhone Calendar regularly. And it is common sense that logging in the same Apple ID and enabling calendar sync on iCloud would sync iPhone calendar events to iCloud. Yet iPad/iPhone calendar not syncing issues might come up unexpectedly at intervals.

Now, if your iPhone calendars don't sync with iCloud or iCloud calendars won't sync with your iOS device, what should you do next? OK, just read on to learn a dozen solutions to fix iPhone calendars not syncing on your own.

iphone calendar not syncing

Part 1: 15 Quick Solutions to Fix iPhone Calendar Not Syncing

Why is my calendar not syncing with my iPhone? Why does my calendar not sync with iCloud? Well, the reasons are a bit complicated, and it would take too long to tell that in full.

You know, it is far less practical to dig deep into this complex problem than fixing common iPhone calendar problems with quick techniques. Now, let's see how to get it settled in feasible ways.

Solution 1: Check Your Internet Connection

First and foremost, you're supposed to check the Internet connection. You can go to Safari and visit If the page doesn't load, you can:

  • Make sure your router is on, and you are within range.
  • Ensure the WiFi is on, and you can see your network.

fix iphone calendar not syncing by checking internet connection

Read Also:

Solution 2: Check Date and Time Settings on iPhone

iCloud calendar not syncing occurs if your device has an outdated date or time. Here's how to check it:

  • On your PC, go to Settings > Date and Time to check this.
  • On your iPhone, browse to its Setting > General > Date & Time and set it to automatic.

fix icloud calendar not syncing by checking data and time settings

Solution 3: Use the Same Apple ID on Your Device

Sometimes, you find iPad and iPhone calendar not syncing, for you haven't log in with the same Apple ID on your device. To check this, on your iPhone, go to Settings > [your name] and verify whether the ID is in accordance with the one on your other devices.

Solution 4: Check iCloud Storage

Ensure you have not exceeded the iCloud storage limit or the limits for iCloud Contacts, Calendars, and Reminders. If there is no free storage, you can upgrade your iCloud plan or get rid of anything unwanted saved in the space. (Want to know how to cancel iCloud storage plans? Tap here)

fix ios calendar not syncing by checking icloud storage

Solution 5: Update iOS

The outdated OS might be responsible for iOS calendar not syncing with iCloud. To update iOS on your iPhone, go to its Settings > General > Software Update". If there is an iOS version available, tap "Download and Install" > "Details" > "Install Now".

fix icloud calendar not syncing with iphone by updating ios

Solution 6: Change Default Calendar

Head to iPhone's Settings > Calendar > Default Calendar. Select a calendar under iCloud to make it default. For the items that have already on the local calendar, just manually add them to the Calendar under iCloud.

Solution 7: Check Apple System Status

There might be an issue with Apple's servers, giving rise to iCloud calendar not syncing with iPhone/iPad. To check it, you can visit Apple's System Status page. If the server is down or Apple is repairing it, you can find the iCloud Calendar below and try to resolve the iCloud calendar not syncing issue shortly.

fix calendar not syncing on iphone by checking apple system status

Solution 8: Turn off Calendars and Turn It Back on

Here's the tutorial:

  • Go to your iPhone's Settings > [your name] > iCloud > disable Calendar sync by switching the tab nearby Calendar to your left.
  • A few minutes later, navigate to Settings > [your name] > iCloud > enable Calendar sync.
  • After that, wait a few minutes to see if all calendars have been synced.

Check if You Need:

Solution 9: Log out of iCloud and Log in Again

If you regularly encounter the calendar not syncing on your iPhone and know your network is stable, just try to log out of the iCloud account and then sign in back again. To do so, go to your iPhone Settings > iCloud > Sign Out > confirm the action > Keep on My iPhone. Subsequently, log in to your iCloud account again.

fix calendar not syncing with iphone by logging out icloud and logging in

Solution 10: Sync iCloud Calendar Manually

Syncing iCloud manually might help fix iCloud calendar not syncing on iPhone or iPad. Here are the steps:

  • Go to, log in to your account and select the Calendar feature from its Home page.
  • Select the calendar you wish to sync.
  • Click the share icon.
  • Enable the option to make the calendar public.
  • Copy its unique link.
  • sync icloud calendar manually to fix ipad and iphone calendar not syncing

  • Go to Outlook or any other service. (Learn how to sync Outlook calendar with iPhone)
  • Add the iCloud calendar you have earlier selected.
  • If you wish to link the iCloud calendar with Outlook, there is an option to add a calendar manually.
  • Add it from the Internet and submit the iCloud calendar URL here.

Solution 11: Refresh the Calendars App

If you find your iCloud calendar is not synced with your iPhone running iOS 11, you can refresh the app as follows.

  • Open the Calendars app on your iPhone.
  • Click Calendars at the bottom of your iPhone's screen.
  • Perform a pull-to-refresh on your phone.

Solution 12: Edit the Registry in Windows

Some iPhone owners find that editing the registry in Windows might help address iCloud calendar not syncing. Here are the directions:

  • On your Windows PC, launch the Run prompt by pressing the "Windows + R" keys.
  • Input "regedit" and tap "Enter".
  • This will open the "Registry Editor" window on your computer.
  • Browse the "HKEY_CURRENT_USER" section.
  • Visit Software Microsoft Office Outlook Addins > Apple.DAV.Addin.
  • Select the "LoadBehaviour" section and ensure the Data value text is set to 3.

edit the registry in windows to fix iphone calendar not syncing

Solution 13: Update Apple Software on PC

You can also try to fix the iCloud calendar not syncing with iPhone by updating the Apple services on your PC. For this, just go to the search option on the taskbar and look for Apple services. A dedicated window for the Apple Software services will appear, from where you can check for updates or install the updates available.

Solution 14: Verify the Status of Port 443

The port error might be the culprit for the iCloud calendar not showing up on iPhone or even not syncing. Here's the manual for checking Port 443 on your system:

  • Run the Command Prompt as an administrator.
  • Enter the following command "netstat -an | find "443" to check the status of Port 443.
  • verify the status of port 443 to fix icloud calendar not syncing

  • If this port is closed, you can manually open it.
  • Finally, disable the firewall or anti-malware service on your PC.

Solution 15: Restart Your iPhone and Computer

Rebooting your device and computer is helpful in addressing issues related to Apple devices. This could be the easiest way to check if iPhone calendars sync. If it doesn't look good, go ahead to check the ultimate solution to avoid the calendar not syncing.

restart iphone and computer to fix ios calendar not syncing

Part 2: Ultimate Solution - Back Up and Restore iPhone Calendar to Avoid Not Syncing

Since the iPhone calendar not syncing with iCloud often annoys you and us, it's much wise to pick a professional program to back up and restore your iPhone calendar smoothly. Well, MobiKin Assistant for iOS (Win and Mac) can do this independently without any trouble.

This advanced tool lets you back up your iPhone calendar to a computer securely and import the backup file from PC/Mac to the same or another iPhone seamlessly.

Major features of MobiKin Assistant for iOS:

  • Sync iPad/iPhone calendars to a computer smoothly, and vice versa.
  • It also works for Contacts, Video, Photo, Music, eBook, SMS, Notes, Safari Bookmarks, Voice Memo, Podcast, Ringtone, Playlist, and more.
  • It is also an iPhone file explorer/manager, controlling iOS data and iTunes backups on computers directly.
  • Back up and restore data between iDevices in a direct manner.
  • Copy iTunes backups from PC/Mac to an iDevice.
  • Work well with overall iDevices, covering iPhone 12/12 Pro (Max)/12 mini, iPhone 11/11 Pro/11 Pro Max, iPhone X/XR/Xs/Xs Max, iPhone 8/8 Plus, iPhone 7/7 Plus, iPhone 6/6S/6 Plus, iPod, iPad, etc.
  • It can well protect your privacy.

ios assistant for win ios assistant for mac

How to use Assistant for iOS to sync iPhone calendars easily?

Step 1. Launch the program and let it detect your iPhone

Use a USB cable to create a connection between your iPhone and a computer. Then launch the tool, and it will ask you to trust the computer on your phone. Just touch "Trust" on your iPhone and tap "Continue" on the software.

trust this computer on iphone or ipad

Step 2. Preview and select the calendars you want

After the successful recognition, you'll get the main screen of this utility. Now, click "Calendars" from the left menu. Soon, you can preview and select the items from the right pane of the program interface.

main screen of assistant for ios

Step 3. Export/import calendars seamlessly

Click "Export" to sync the iPhone calendar to your computer. And after that, you can tap "Import" to copy the calendars saved on this computer to any iOS device anytime.

sync iphone calendar smoothly with mobikin assistant for ios

Final Words

There are fifteen quick solutions out there to fix iOS calendar not syncing in this post. Yet, they are not guaranteed to work. That is, you may still be puzzled by the iPad/iPhone calendar not syncing issue after trying each of the fixes out.

So, to make your iPhone calendar synchronization journey smoother and easier, simply go for MobiKin Assistant for iOS - the ultimate tool - to sync your iPhone calendar and manage other iPhone content painlessly.

ios assistant for win ios assistant for mac

Related Articles:

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Users Guide: How to Sync Yahoo Calendar to iPhone?

Ultimate Guide about Outlook to Google Calendar Sync

iPhone Calendar Manager: How to Manage iPhone Calendars on PC

How to Transfer Calendar from Android to Android?

Alleny Gavin
Alleny GavinChief Editor
A chief editor at MobiKin, brings over a decade of experience in technical writing and holds a B.A. in English Literature. With a background as a Project Manager in the IT industry, he has authored 1000+ articles on, offering expert solutions for iOS issues. Gavin, a tech enthusiast, effortlessly recommends software with passion and extensive expertise in smartphones and software.
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