This guide will show you how to create a new shared calendar in Office 365, and then share it with someone outside your organization. We’ll also cover how to handle folks using Google or calendar systems other than Exchange. It should take a couple minutes to complete, and you should not need administrative privileges.
From scratch: How to create a shared calendar in Office 365
Sign into the Office 365 web app, and navigate to Outlook calendars. We’ll start by creating a new calendar that we will then share with outside users. In the left side of your Outlook calendar, click the plus sign next to “My Calendars.” This will add a new calendar to the bottom of the list. Give it a name then you’re ready to move on to the next step.
Permissions: Set up a shared calendar in Office 365
Now that you have the calendar ready, follow these steps to set up shared permissions in Office 365 for users who are not part of your organization.
1. Right click the calendar you want to share
This will bring up a context menu with options for the calendar you selected.
2. Click “Permissions”
You have control of what details on your calendar can be seen by others. When you click Permissions, a new panel for managing the calendar’s access rules will open. If you currently share the calendar with anyone else in your Office 365 account or outside your organization, those account names will show up here. Users inside your organization will have two extra options for “Delegate” and “Editor,” which come with the ability to edit this calendar’s rights.
3. Change “Public Calendar” permissions to “Availability only” and click save
This change allows people outside your organization to visit a secret link and view a read-only version of your calendar. By setting your calendar to “Availability only,” others will see only event times. If you are comfortable with sharing more information, “Full Details” will show everything.
4. Right click the calendar again, and select “Share Calendar”
With the settings changes you’ve made so far, it’s possible for people without an Office 365 account to view your calendar. Now you can add more users without worrying about their calendar system.
5. Add the email of the external person you want to share with
Type the email address into the “Share with” field. Outlook will automatically detect if the person is inside your organization and group them appropriately.
6. Pick permissions for calendar visibility and click save
FYI: These permissions will work only for people using Outlook (i.e. Office 365 and Exchange). Everyone else will see the permissions set in step 3. Since you won’t always know which calendar system a person uses, it’s safer to cover both options.
If you’re sharing the Office 365 calendar with a specific person, you will most likely want them to have the full details of your meetings. If you want them to see only availability, feel free to pick a lower permission level instead. Once you press save, Outlook will automatically send email notifications to everyone you shared your calendar with.
Since you are sharing your calendar with a person outside your organization, you will not be able to give them edit permissions.
7. Repeat these steps for each of your multiple calendars in Office 365
If the person you shared the calendar with uses Office 365, Outlook, or another kind of Exchange app they will receive an invitation and be able to add your calendar to their list.
Dealing with cross-platform permission issues
Unsurprisingly, these steps on how to use Office 365 shared calendar with external users have a couple limitations for the average organization.
The above process only works for people also on Exchange or Office 365. Google users can view the calendar via a link emailed from Outlook. However, they will not be able to access your shared calendar invitation without a third party app due to different calendar formats.
Google (and non-Outlook) users will receive an email that looks like this:
The invitation will include a link which shows a public version of the calendar. If you’ve set your calendar permissions to allow public viewing (via steps 3-5), the shared user can bookmark it for reference. If you skipped those steps, they will not have any way to access your calendar, since the link shared will not allow public access: