Set up Calendar Interop

Allow Calendar users to see Exchange availability data

Next, set up Microsoft® Exchange availability sharing to allow Google Calendar users to see availability information for Exchange calendar users. 

If you are using a G Suite domain with an alias, make sure that you have set up your alias domain correctly before continuing. For details, see Set up Calendar Interop using a domain alias.

Set up Exchange calendar availability sharing

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Step 1: Set up your Exchange users
  1. Make sure each Exchange user has an Exchange account with an associated mailbox.
  2. Make sure each Exchange user satisfies one of the following requirements:

    Note: You also need to check that the user doesn't have a personal Google account that uses the domain name of your organization. This can create a conflicting account. Learn more about conflicting accounts.

Enable full event detail lookups

To use full event detail lookups, check the calendar's visibility when you set up mailboxes. You must ensure the calendar's visibility is set to at least limited event details (the default visibility is to expose free/busy information only). Then, the Exchange calendar event details are visible to Google Calendar users.

You can expose limited event details for an individual mailbox using the following script:

Set-mailboxfolderpermission –identity
($Mailbox.alias+’:\calendar’) –user Default –Accessrights

For all mailboxes, use:

$allmailbox = Get-Mailbox -Resultsize Unlimited
Foreach ($Mailbox in $allmailbox)
{Set-mailboxfolderpermission –identity
($Mailbox.alias+’:\calendar’) –user Default –Accessrights LimitedDetails}

Step 2: Enable Exchange internet connectivity

On port 443, enable inbound internet connectivity so that the Exchange server can be reached by Google Calendar. This requires an SSL certificate issued by a trusted public internet root Certificate Authority.

For details on certificates, see the following Microsoft instructions:

To block all incoming traffic except for requests originating from Calendar Interop, whitelist the following IPv4 range:

If you use IPv6, whitelist the following IP blocks:

  • 2001:4860:4::/64
  • 2404:6800:4::/64
  • 2607:f8b0:4::/64
  • 2800:3f0:4::/64
  • 2a00:1450:4::/64
  • 2c0f:fb50:4::/64
Step 3: Create an Exchange role account

Create an Exchange role account. The role account should be a normal mailbox account. The account is only for availability lookups. Google Calendar uses the account to authenticate with your Exchange server in order to look up the availability details of Exchange users. Events must be shared with the Exchange role account to be visible in Google Calendar.

For details on creating a mailbox account, see the following Microsoft instructions:


  • If you have an existing account that you use for OrgWide availability lookups from untrusted forests, you can reuse that account.
  • To avoid service disruption, it's recommended that you turn off password expiration for the role account.
Step 4: Set up the Admin console
  1. In your Admin console, go to Apps and then G Suite and then Calendar.  

    Important: Make sure you sign in to your primary domain.

  2. Click Calendar Interop management.
  3. Click Interoperability settings.
  4. Select Enable Interoperability for Calendar.
  5. Under Type, select Exchange Web Services (EWS).
  6. Under Exchange Web Services URL, enter the URL of the Exchange Web Services server associated with your Exchange server. This is the same Exchange server where you created the role account.


    • Your server’s EWS server URL is most likely https://<Exchange server hostname>/EWS/Exchange.asmx.
    • You can verify the URL by running the following command in Exchange PowerShell:
      Get-WebServicesVirtualDirectory | Select name, *url* | fl
    • If you have multiple URLs, use ExternalUrl.
    • If you have multiple Exchange servers (for example, you're using a hybrid Exchange/Office 365 environment) and you want Calendar users to see availability of Exchange users in your entire environment, make sure the EWS server URL is from a server that can access availability for all Exchange users.
  7. Under Exchange Role Account:
    1. In the format, enter the Exchange role account username.
    2. Click Enter Password and enter the password for the role account.
    3. Reenter the password to confirm. 
  8. (Optional) Under Interoperability features, select the level of detail to share:
    • Full event details to see events from Exchange as well as Calendar.
    • Room booking to schedule Exchange rooms from Calendar.
  9. Click Save.

Note: To view previous changes to the Calendar Interop settings, click the Audit log link.

Next step

Allow Exchange users to see Calendar availability data

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