How to Sync Outlook Calendars - 2025 Guide

If you are an Outlook user and would like to sync two or more Outlook Calendars, streamlining the availability and avoiding confusion between team members, this article is for you.

In this article, we’ll explain the issues of managing multiple Outlook Calendars, why publishing and importing Outlook Calendars don’t ultimately sync them, and the actual solution to sync Outlook Calendars.

Prefer video? Here is our step-by-step tutorial on syncing Outlook Calendars in real time.

How to Sync Two Outlook Calendars via Calendar Sharing Feature

Outlook offers a way to publish a Calendar and import it into another account. This doesn’t mean that the calendars are synced, publishing a calendar and importing it into another account is just a means for you to view multiple Outlook calendars under one Outlook account, but ultimately, the calendars are separate.

Let's assume you have two Outlook calendars, calendar A and calendar B. To manually sync two Outlook Calendars, you'd have to follow these steps:

1. Sign in to Outlook (Calendar A). Open the Microsoft Outlook Page and click Sign In to access the Outlook web app.
2. Select the "Settings" icon on the header: The settings icon is located in the top right section of the page header. Make sure you're logged in to the first Outlook Calendar A (per our example).
   
   
3. Click Calendar (next to the calendar icon), then click Shared Calendars.
   
   
4. Select the calendar you want to share. This is the first section of the "Shared Calendars" tab, as it asks you to select the calendar you want to share.
5. Find the "Publish Calendar" Section: The "Publish Calendar" section is located at the bottom of the page. In this section, find the link to the Outlook calendar you’d like to sync with the other Outlook Calendar. 
   
   
6. Click Calendar, then click Can view all details. In this step, you can either choose to sync all event details or not. For security reasons, choosing "Can view when I'm busy" is the recommended way to go.
   
   
7. Click Publish.
   
   
8. Copy the generated ICS URL: After clicking 'Publish', Outlook generates an ICS URL, we need to copy it.
   
9. Open Outlook on the web, and log in to Calendar B. After copying the secret address from Calendar A, now it's time to go to outlook.live.com again and sign in to Calendar B.
10. Click "Add Calendar". The 'Add Calendar' button is located on the left sidebar of the page, below the calendar.
    
11. Click "Subscribe from web". The 'Subscribe from web' menu item is located on the left sidebar of the page. This enables us to import Calendar A into Calendar B.
    
12. Paste the URL you copied from Outlook Calendar A. Now we need to paste the ICS URL we copied instep 8.
    
13. Click the "Import" button.

After the process is finished, you'll be able to see Calendar A into Calendar B. The caveat is that you’re the only one who sees all calendars in one view; if your team members book time through your work calendars, they won’t be able to see events in imported Outlook Calendars.⁠

Pros of manually syncing Outlook Calendars

Even though the sharing feature on Outlook Calendar doesn't sync the calendars, it has some benefits:

• You can view multiple calendars in one account: If you manage multiple Outlook calendars in separate accounts, you can share and import them into a single account, eliminating the need to juggle between accounts

Downsides of manually syncing Outlook Calendars

• Sharing doesn't sync Outlook calendars: As mentioned above, sharing only makes it easier for you to view all your calendars in one account and view, but ultimately, the calendars are still separate. If team members book a time with you in one calendar, they won't be able to see that you're booked in your imported/shared calendars.
• Updates take up to 24 hours to propagate: It's worth noting that updates from a shared calendar might take up to 24 hours to propagate.
  For example, you imported Acme Inc. into Wayne Enterprises Outlook Account. If someone books a meeting in Acme Inc., it might take a while for that meeting to be propagated into the imported Acme Inc. in Wayne Enterprises Account.
• Limited sharing options: When publishing an Outlook Calendar, you can either choose to view all event details or none, there is no in-between. When selecting the option to view all event details, your calendar becomes public, and anyone who has the URL can view your events.
• Will lead to double bookings: All that calendar sharing does it allow you to view the imported calendar in the same view as the other calendars. It doesn't mean that coworkers who view your availability in Calendar A are able to see the Calendar B you imported into Calendar A. Manually syncing is useful for viewing multiple calendars in one view, but doesn't account for double-bookings.

How to Sync Outlook Calendars automatically?

To truly sync the events between two Outlook Calendars (or more), you have to use a Calendar sync tool like OneCal.

OneCal syncs multiple Outlook Calendars in real-time, so your Outlook Calendars reflect availability and don’t get double booked.

With OneCal, you can:

• Two-way sync of multiple Outlook Calendars
• Customize event cloning settings and adjust your privacy preferences
• Sync as many calendars as you want

To automatically sync two (or more) Outlook Calendars in real time, follow these steps:

1. Sign Up for OneCal (for free)
   
   
   You can create a free OneCal account for free, without the need for a credit card. You can delete your account at any time, there are no strings attached.
2. Connect your Outlook calendars
   
   
   OneCal allows you to connect as many Outlook calendars as you want. We use official Outlook APIs to connect with your calendars and never store event details. You can revoke the access to OneCal at any time.
   
   After authorizing your Outlook Account, you can choose to connect the calendars that belong to that account:
   

3. Click ‘Start New Sync’

   

   
   After you connect your calendars, you’re redirected to the Calendar Sync feature. You can click the ‘Start New Sync’ button to initiate a calendar sync between your calendars.

4. Name the sync and choose the sync direction

   

   
   OneCal offers one-way and multi-way syncs.

   One-way syncs allow you to clone events from a calendar to one or more calendars. This is useful when you want to sync your personal calendar with your work calendar by only sending personal events to your work calendar and not vice versa.

   Multi-way syncs keep multiple calendars in sync in real-time. For example, if you have two Outlook Calendars, you can select multi-way sync, and OneCal keeps both calendars in sync. As soon as an event is created or updated in any of the Outlook Calendars, OneCal syncs it to the other calendar.

   For the purpose of this article, we’ll sync two Outlook Calendars, and we want to keep them in sync, so we choose the ‘Multi-way’ sync.

5. Choose which Outlook Calendars to sync

   

   
   OneCal allows you to sync multiple calendars at the same time without the need to create multiple configurations. To sync two Outlook Calendars, we’ll select the two Outlook Calendars we connected to OneCal and click ‘Next’.

6. Choose what event properties to sync

   

   
   The most powerful OneCal feature is the flexibility it offers regarding calendar syncing. You can sync all event details or none of them or choose the properties individually.

   If you want complete privacy, you can add a custom title to clone events (such as ‘Busy’), so you block the time on all your calendars by not exposing other details.

Your Outlook Calendars are synced 🥳

All your Outlook Calendars are now a mirror of each other, in this example, the two Outlook Calendars we choose to sync. If a coworker books a time with you, you’re sure that you won’t be double booked, as the calendar has events from all the other calendars.

You can also leverage the OneCal Calendar view to view your synced Outlook Calendars in one view:

What are the benefits of using OneCal to sync Outlook Calendars?

• Seamless Real-Time Synchronization Between Outlook Calendars. Once you've established this synchronization, you can have complete confidence that your events will consistently and reliably transfer without any concerns.
• Privacy-focused syncs. This synchronization guarantees your control over the privacy of the calendars you sync. It's important to note that workspace administrators won't have access to view events or calendar details that are replicated by OneCal.
• Real-time, reliable Outlook calendars sync. When attempting manual synchronization through the import method, you have to go through a 13-step process to sync one Outlook calendar with another Outlook Calendar. After following these steps, the sync might fail, and the changes don't happen in real-time. With OneCal, your calendars stay in sync automatically, and you can sync multiple Outlook calendars in one go.
• No Double Bookings: Unlike calendar sharing, OneCal directly clones events into your Outlook Calendar. This means that coworkers are able to see your real availability and never double-book.

What does syncing Outlook Calendars solve?

The main problem we face when managing multiple Outlook Calendars is that colleagues don’t know your availability when scheduling meetings through your work calendars.

Assume you’re a consultant at Wayne Enterprises and Acme Inc.; Colleagues at Acme Inc. don’t know when you’re busy at Wayne Enterprises and vice versa.

Example: Martha from Wayne Enterprises booked a meeting with you, but she doesn’t know that you’ve got a booking at Acme Inc. at the same time. This means that you’re double booked and will have to go back and forth with Martha to reschedule the meeting.

If your Outlook Calendars were synchronized, Martha would see that you’re busy at that time and would find another time slot to book with you.

Automatically Sync Multiple Outlook Calendars Using OneCal

OneCal is the most reliable calendar sync platform in the market, offering seamless Outlook Calendar sync and advanced privacy options.

With OneCal, you can sync two or more Outlook Calendars in minutes and never have to worry about double bookings and confusion between coworkers.

Sign Up for OneCal for free to experience real-time Outlook Calendar sync and leverage other features like Scheduling Links, Calendar View, and more.