How to Share Your Outlook Calendar (Internally and Externally)

How to share your Outlook calendar depends on who you are sharing it with. Sharing with a colleague inside your Microsoft 365 tenant is straightforward and supports granular permission levels from free/busy only up to full event details. Sharing with someone outside your company — a client, a contractor, a vendor — follows a different path, relies on publishing a link or an ICS subscription URL, and is governed by your organisation's external sharing policy.

That internal versus external distinction is where most sharing failures originate. The two paths look similar in the interface but behave differently in practice and fail for different reasons. A sharing invitation sent to an external recipient can appear successful on your side while the recipient sees nothing but empty blocks, because the permission level was set too low or external sharing was disabled by an administrator.

This guide covers both paths for Outlook on the web and classic Outlook desktop. It also covers the ICS subscription route, the platform differences that affect which options appear in your interface, and the most common reasons calendar sharing stops working in Microsoft 365.

Before you start: permission levels and admin policy#

Before you share, understand what the three Outlook calendar permission levels actually show a recipient. The level you choose determines how much detail appears, and it cannot be overridden by the person you share with.

For external sharing specifically, your organisation's Microsoft 365 admin controls a global switch. If external sharing is disabled at the tenant level, the publish option will be greyed out or missing entirely, regardless of what you attempt. If the option is not visible, check with IT before assuming it is a local settings issue.

How to share your Outlook calendar with a colleague inside your organisation#

The steps below use Outlook on the web, which is the most complete interface for calendar sharing in Microsoft 365. Classic Outlook desktop follows the same logic but reaches the sharing panel differently: right-click the calendar in the left pane, choose Share, then Share Calendar. An email compose window opens with a pre-formatted sharing invitation. From there the recipient and permission level work the same way.

1. 1

   Open the calendar view

   Go to Outlook on the web at outlook.office.com or outlook.microsoft.com and click the calendar icon in the left navigation bar.

2. 2

   Right-click your calendar

   In the left pane under My calendars, right-click the specific calendar you want to share. You can share your primary calendar or any secondary calendar you own.

3. 3

   Choose Sharing and permissions

   Click Sharing and permissions from the context menu. A panel opens on the right side of the screen listing anyone who already has access.

4. 4

   Enter the recipient's name or email

   Type the name or email address of the colleague you want to share with. For internal colleagues, their name appears in the directory as you type. Select them from the suggestions.

5. 5

   Set the permission level

   Use the dropdown next to their name to choose Availability only, Limited details, or Full details. For most colleagues, Limited details or Full details is the appropriate choice. Availability only hides all event content.

6. 6

   Click Share

   The colleague receives an email invitation with a link to add your calendar to their view. Once they accept, your calendar appears alongside their own in the left pane.

How to share your Outlook calendar with someone outside your company#

External sharing works by publishing your calendar as a link. There are two link formats: an HTML link that opens in a browser, and an ICS link that the recipient can subscribe to in any calendar application. The ICS route is more practical because the subscriber's calendar updates automatically whenever you add or change events, with no need to reshare.

Publishing is managed through Outlook on the web. Classic Outlook desktop does not have a direct Publish a calendar option in the same location — use the web interface for external sharing.

1. 1

   Open Calendar settings

   In Outlook on the web, click the gear icon in the top right to open Settings. Search for 'Shared calendars' or navigate to Calendar > Shared calendars in the settings pane.

2. 2

   Find the Publish a calendar section

   Under Shared calendars, locate the Publish a calendar section. If it is greyed out or absent, external publishing has been disabled at the tenant level by your admin.

3. 3

   Choose your calendar and permission level

   Select which calendar to publish from the first dropdown. In the second dropdown, choose the permission level: Availability only, Limited details, or Full details. The same visibility rules apply as internal sharing.

4. 4

   Click Publish and copy the link

   After clicking Publish, two links appear: an HTML link for web browsing and an ICS link for calendar subscriptions. Copy the ICS link to give the recipient a self-updating view of your calendar.

5. 5

   Send the ICS link to your external contact

   Paste the link into an email or message. The recipient opens it and their calendar app — Google Calendar, Apple Calendar, another Outlook account — offers to subscribe. Their view updates automatically as your calendar changes.

Once published, the ICS link acts as a live subscription. External contacts see your calendar at the permission level you set without needing a Microsoft account. If you later regenerate the link — for example, to change the permission level — the old link stops working and you need to send the updated one to anyone who was using it.

Sharing options across Outlook web, desktop, and mobile#

The calendar sharing experience varies across Outlook surfaces. Outlook on the web is the most complete: it provides both the internal Sharing and permissions panel and the external Publish a calendar option. Classic Outlook desktop supports internal sharing through a slightly different flow but lacks a direct publish path for external links. Outlook mobile displays shared calendars but does not expose sharing management settings.

When calendar sharing is not working in Microsoft 365#

Most calendar sharing problems fall into a small set of patterns. The table below maps symptom to cause so you can identify the right fix without trial and error.

A faster way to handle the inbox coordination that follows#

Sharing a calendar solves the visibility problem. What it does not handle is what comes next: the emails asking to confirm a slot, the threads that open a rescheduling conversation, the follow-ups from contacts who saw availability and want to book time. For anyone managing a full calendar alongside a heavy inbox, that cycle of availability question, reply, reschedule, and confirmation is where a significant amount of time actually disappears each week.

We build AI Emaily — an AI-native email client that connects your Outlook account alongside every other inbox you use. Its Copilot mode prepares scheduling replies, rescheduling responses, and meeting confirmations in your voice and holds them for one-tap approval before anything sends. Autopilot handles the fully routine coordination on its own, with an audit trail and undo on every action. The calendar sharing itself stays in Outlook; the surrounding inbox work runs through AI Emaily. Start a 7-day free trial at aiemaily.com or review plans at aiemaily.com/pricing.