MailboxUsage report

Important: These reports are deprecated as of January 29, 2018. We recommend that you use the Microsoft Graph Mailbox usage reports instead.

The MailboxUsage REST URI provides summary statistics about the Office 365 organization's mailbox usage. The report includes the number of mailboxes, how many mailboxes are getting full, and how many are not used much. To get more information about a particular mailbox, use this report with the MailboxUsageDetail report.

Last modified: December 12, 2017

Applies to: Office 365[?ODATA options]

The following fields can be specified in $select, $filter and $orderby ODATA2 query options. All fields are returned if no $select option is provided.


WCF Type*

EDM Type*

[In/Out]** Description

Example values

Added in service version




[In/Out] The end date and time of the reporting period. For more information about reporting periods, see below.

Short Date (for example, 03/10/2013) or Date Time with quotes (for example, "03/10/2013 4:55 PM")





[In/Out] The number of Office 365 mailboxes that were over their warning size. For more information, see the Remarks section.






[In/Out] The number of Office 365 mailboxes that were used on fewer than 25% of the days covered by the reporting period.






[In/Out] The GUID of the organization.





None specified

[In/Out] The domain name of the organization.





[In/Out] The total number of mailboxes that were completely inactive during the reporting period.






[In/Out] The total number of mailboxes existed during the reporting period.

*WCF Type refers to the .NET Framework data type assigned to the field when you create a Windows Communications Framework (WCF) Service Reference in Visual Studio. The EDM Type refers to the ADO.NET Entity Data Model (EDM) types returned in Atom-formatted reports.

**[In/Out]: For more information, see the Input parameters and report output columns section.

Office 365 mailboxes have two defined quota levels: a warning level and a size limit. When the mailbox is over the warning size limit, the email client typically instructs the user to delete unneeded mail. The user can still send and receive mail, until the size limit is reached, at which point they cannot send or receive mail. The MailboxesOverWarningSize property indicates the number of mailboxes that are over either of those limits (it's assumed the size limit is set larger than the warning size).

Each entry in the report includes several fields of metadata. For more information, see Common metadata returned by the Office 365 Reporting web service.

Coming soon…

The [In/Out] indicators in the fields table have the following meanings:

  • Fields marked [In] in the fields table are primarily intended for use in $filter=, $orderby= and other query options that restrict which entries the report returns. Fields marked [In] in the fields table can be included the $select= option and they will appear in the report entries, but they will contain no useful data.

  • Fields marked [In/Out] in the fields table can be used in both column selection ($select=) and entry restriction ($filter= and $orderby=) options. When you include one of these fields in the $select= option, they will appear in the report entries and will contain useful data when it is available.

The MailboxUsage report was introduced in Office 365 service version 2013-V1. For more information, see Versioning in the Office 365 Reporting web service.

The MailboxUsage report returns the same information as the Get-MailboxUsageReport Windows PowerShell cmdlet.

Note Note

This cmdlet is deprecated. We don’t recommend that you use it in your production environment.

The account you access the reports from must have administrative permissions in that Office 365 organization. If the account can view this report in the Office 365 control panel, then the account has permissions to retrieve the data from the REST web service. This report requires the user to be assigned to the View-Only Recipients Role. In the default Office 365 permissions structure, users with the following administrator permissions can access this report: billing administrator, global administrator, password administrator, service administrator, and user management administrator.

Information available through these reports can be separated into one-day periods, starting at midnight of the time zone reported by the calling application in the HTTP X-timezone header.

The information for this report is available for a period of one year or until the subscription is cancelled.

Events may be delayed by up to 24 hours before they appear in a report.