How to Share an Outlook Calendar Between Two Domains

Yes. You can share an Outlook calendar with someone whose email address belongs to another domain, provided your Microsoft 365 or Exchange administrator allows external sharing. In Outlook on the web, open Calendar, choose the calendar’s sharing or permissions option, add the person’s email address, and select what they are allowed to see.

What sharing between domains means

A domain is the part of an email address after the @ sign, such as example.com. Sharing between two domains usually means that one person has a work or school account in one Microsoft 365 organization and the recipient has an account in a different organization. The organizations might use different domains, or they might use different Microsoft 365 tenants while using similar-looking domains.

The domain difference does not, by itself, prevent sharing. Outlook calendar sharing is governed mainly by Exchange settings and the policies of the organization that owns the calendar. An administrator can permit external sharing, limit the amount of information users may share, or block it entirely. A user generally cannot override an organization-wide restriction from Outlook.

Sharing is not the same as transferring a calendar or merging two organizations. The calendar remains in its owner’s mailbox; the other person receives permission to view it, or in some cases to edit it. The owner can normally change or remove that permission later.

Choose the right access level

Before sending an invitation, decide how much information the recipient needs. Outlook’s available choices can vary with the organization’s policy and the calendar-sharing experience, but common levels include seeing only when the owner is busy, viewing titles and locations, or viewing more complete event details. Editing permission is a separate, higher level of access and should be granted only when needed.

Free/busy only: The recipient can see whether time is marked as busy, but not the event’s subject or other details. This is useful for coordinating meeting times.
Limited details: The recipient can see selected information, often including subjects and locations, depending on the permission shown in Outlook.
Full details: The recipient can read more of the event information. Check what the selected option reveals before sharing sensitive calendars.
Can edit: The recipient can make changes to events on the shared calendar. This is appropriate for a delegate or close collaborator, not merely someone who needs to check availability.

Permission names and options are not identical in every Outlook version, and administrators can restrict the highest available detail level. A calendar invitation also does not necessarily expose private events in the same way as ordinary events; the owner’s private-event settings and the recipient’s permission level matter. When in doubt, use the least access that supports the task and confirm what the recipient can actually see.

Share it in Outlook on the web

Outlook on the web is a practical starting point because it offers a consistent calendar-sharing interface for Microsoft 365 work and school accounts. Use the account that owns the calendar, not the recipient’s account.

Sign in to Outlook on the web with your work or school account and open Calendar.
In the calendar list, locate the calendar you want to share. Open its context menu, or select it and choose Sharing and permissions. The wording and location can vary slightly with the current Outlook interface.
Enter the recipient’s full email address. Check carefully that it is the address they use to access their organization’s account.
Select the permission level offered by Outlook, such as free/busy visibility, viewing details, or editing if that option is available.
Choose Share or the equivalent confirmation control. Outlook sends an invitation if external sharing is allowed.

The recipient should open the invitation while signed in to the account associated with the invited address, then accept or add the calendar as prompted. If they have more than one Microsoft account or work profile, they may need to switch accounts. If Outlook reports that sharing is unavailable, or the recipient sees an access error, the next step is usually to ask the calendar owner’s administrator to check the sharing policy.

Share from Outlook for Windows or Mac

In the current Outlook for Windows, open Calendar, find the calendar in the calendar list, and use its context menu to open Sharing and permissions. Add the recipient and choose an allowed permission level. The precise labels can change as Microsoft updates Outlook, so if the sharing control is not visible, use Outlook on the web with the same work or school account.

In classic Outlook for Windows, the traditional route is to open Calendar, select the calendar, and use Home > Share Calendar on the ribbon. This command is generally available for Exchange calendars, but not every account type or configuration supports the same sharing options. Follow the invitation dialog and select a detail level that is permitted by the organization.

Outlook for Mac also supports calendar sharing for supported Exchange and Microsoft 365 accounts, but the controls can differ by release. If the sharing or permission control is not apparent in the Calendar view, Outlook on the web is a reliable alternative. These instructions apply to Outlook for Microsoft 365; a personal Outlook.com account or an older perpetual version may present different menus and capabilities.

What administrators control

For a work or school calendar, external sharing is an Exchange organization setting as well as a user action. Microsoft 365 or Exchange administrators can control the organization’s sharing policy, including whether users may share with people outside the organization and the maximum level of calendar detail available to those people. A policy can allow only availability information even when the owner wants to share full event details.

When an entire partner organization needs to look up availability, an administrator may consider organization-level calendar sharing between the two Exchange organizations. This is different from one employee sending an individual calendar invitation: organization-level configuration can support broader free/busy lookups, while individual sharing targets named people and can grant specific calendar permissions. The right approach depends on whether the need is one person, a team, or routine scheduling across both organizations.

If you are the user, give your administrator a concrete request: identify the calendar owner, the recipient’s email domain, the required access level, and whether the need is temporary or ongoing. Avoid asking for unrestricted access when free/busy information will do. Administrators can then check the relevant external-sharing settings and any limits imposed by security policy.

Direct sharing, publishing, and calendar files

Direct sharing is usually the best choice when a specific person should have ongoing access. The owner can grant permission to an identified address and later change or revoke it. Depending on the recipient’s account and the organizations’ configuration, the calendar may appear in the recipient’s Outlook calendar list after they accept the invitation.

Outlook on the web may also offer calendar publishing. The owner can look under Settings > Calendar > Shared calendars for publishing options, if the organization permits them. Publishing can create an HTML link for viewing in a browser and an ICS link for subscribing in a calendar application. These links are not the same as a named-person permission: anyone who obtains a usable link may be able to access the published view, so treat it as sensitive and do not post it publicly. Publishing options and detail levels may be disabled by an administrator.

An ICS attachment is another option for sending a calendar snapshot or selected event information, but it is not equivalent to a live shared calendar. A recipient who imports a file generally does not receive ongoing permission to view future changes in the owner’s calendar. A subscription link can refresh, but update timing depends on the receiving calendar service and is not a substitute for real-time collaboration or editing permission.

Privacy and security considerations

A calendar can reveal more than meeting times. Event titles may disclose customers, projects, medical appointments, travel, or internal plans; locations and attendee lists can add further sensitive context. Review the permission level and the contents of the calendar before sharing it outside the organization. If only a subset of events should be visible, consider using a separate calendar containing only the information intended for the recipient.

Share with a named person’s organizational address when possible, rather than publishing a broadly accessible link.
Use free/busy access for scheduling when event details are unnecessary.
Grant editing rights only to someone who must manage events, and remove access when the work ends.
Follow your organization’s rules for confidential, regulated, or customer information.

External sharing does not automatically give the recipient access to the owner’s email, contacts, or other calendars. It grants only the calendar access covered by the invitation or link. Conversely, removing a recipient from one calendar does not remove access they may have received separately through a group, a published link, or another calendar.

Common problems and how to fix them

The recipient cannot be added: The organization may block external sharing, restrict invitations to approved domains, or require an administrator to configure the policy. Confirm the recipient’s address and ask the calendar owner’s IT team to check the sharing rules.

The invitation arrives, but access is denied: The recipient may be signed in with a different account from the address that received the invitation. Have them open it in a browser where they can select the correct work or school account. If the error persists, the owner’s administrator may need to review external access settings.

The recipient sees availability but not event details: The owner may have selected free/busy access, or the organization may cap external sharing at that level. The owner can check the current permission, but cannot grant more detail than policy allows.

The calendar is missing from Outlook: The recipient may need to accept the invitation or add the shared calendar from the invitation message. Refreshing Outlook or checking Outlook on the web can help distinguish a display issue from a permissions issue. The recipient should not assume that an invitation automatically appears in every calendar app.

Changes do not appear immediately: Direct calendar sharing and ICS subscriptions behave differently. A subscribed ICS feed can update on a delay determined by the receiving service, while a static imported file does not keep itself synchronized. For a shared work calendar, use the invitation-based permission rather than relying on an exported file.

Frequently Asked Questions

Can I share an Outlook calendar with someone using Gmail?
Often, yes, if the calendar owner’s organization permits external sharing. The recipient must follow the invitation or access instructions, and their ability to view it in a particular calendar app depends on that app’s support. A Gmail address does not bypass Microsoft 365 sharing restrictions.

Can two companies share Outlook free/busy information?
Yes, administrators can configure cross-organization calendar availability in supported Exchange environments. That organization-level setup is distinct from an employee sharing one calendar with a named external person, and it commonly focuses on availability rather than full event access.

Can the other person edit my Outlook calendar?
Possibly. The owner must grant an editing permission, and the organization must allow it for that external recipient. If the recipient only needs to schedule around your commitments, free/busy access is safer than edit access.

Why is the Share Calendar option missing?
The account may not be an Exchange or Microsoft 365 account, the selected calendar may not support sharing, or an administrator may have disabled external sharing. Try Outlook on the web and contact the calendar owner’s IT administrator if the option remains unavailable.

Does sharing a calendar expose my whole mailbox?
No. Calendar sharing grants access to the calendar at the selected permission level; it does not by itself grant access to email or the rest of the mailbox. Review the permission and avoid publishing links if you do not want link holders to see the published calendar.

Try it: the Date Difference Calculator: days, months, years and weekdays between two dates, with the DATEDIF formulas.

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