How to check mailbox size in Exchange Server

Mailboxes act as repository of objects like emails, contacts, calendar items and so on. It is important to monitor the mailbox size, so that you can stay informed about quota utilization or violation, and decide when to archive or delete relevant data to free up storage space, and ensure that users send and receive emails without any interruption.

In Microsoft Exchange Server, you can check the mailbox size individually for every mailbox, under the General tab and in Exchange Online the same can be viewed under the Mailbox usage tab. Besides, you can also use PowerShell scripts to configure and monitor message size settings. In case you run a huge organization with thousands of mailboxes it can be time consuming and tedious to monitor all the mailboxes' sizes individually.

Mailbox Size Reports in Exchange Reporter Plus

Exchange Reporter Plus offers a number of pre-configured mailbox storage specific reports, to view details such as the mailbox size, its growth, the quotas, used up space, archive space available, and more. These information help you to plan the available database space wisely.

Exchange Server mailbox size reports:

1. Mailbox Size

Shows the size of mailboxes at the time of report generation.

2. Mailbox Size Growth

Shows the growth rate of the mailboxes over a period of time.

3. Mailbox Size Restrictions

Lists all the mailbox size restrictions such as issue warning at, prohibit send at and prohibit send and receive at limits specified by the administrator.

4. Mailbox Size by OU

Lists the size of all the mailboxes in the specified organizational unit (OU).

5. Current Mailbox Size vs Quota

Compares the mailbox quota size and the actual size.

6. Server based Mailbox Growth

Shows the growth rate of mailboxes for all mailbox servers.

7. Database based Mailbox Growth

Shows the growth rate of mailboxes for all mailbox databases.

8. Archive Mailbox Size

Shows the size of all archive enabled mailboxes.

9. White Space

Shows the available new mailbox space in each database. These new mailbox spaces arise when some mailboxes or mailbox contents are purged.

Steps to generate the mailbox size reports for Exchange Server:

1. Go to Reports tab on the top pane.
2. Navigate to Exchange Server > Mailboxes tab.
3. Choose a report from the set of Size Reports available.
4. Select the Organization for which you want to generate the report, from the drop down.
5. When prompted to create a new task to generate these reports, select click here to task schedule.
6. Enter a suitable Schedule Name and Description.
7. Choose the Gathering Task Name as Mailbox account properties.
8. Set the Schedule Frequency and time for generating the report.
9. Click on Create.

These reports, once scheduled will be generated regularly as per the time set and be mailed to the stakeholders regularly.

Note: White Space & Archive Mailbox Size Reports can be found under: Exchange Server → Storage → Mailbox Database Reports. Generate the White Space report to know the Available New Mailbox Space of all mailbox databases.

Exchange Online mailbox size reports:

1. Mailbox Size

Shows the size of mailboxes on a particular date.

2. Mailbox Size Restrictions

Lists all the mailbox size restrictions such as issue warning at, prohibit send at and prohibit send and receive at limits set for your Exchange Online mailboxes.

3. Current Mailbox Size vs Quota

Compares the mailbox quota size and the actual size.

4. Archive Mailbox Sizes

Shows the size of all archive enabled mailboxes.

5. Mailbox Size Changes

Shows all the mailbox size change activities carried out by the admin during the given period of time.

6. Shared Mailbox Size

Lists the size of all the shared mailbox in your Office 365 tenant.

Steps to generate the mailbox size reports for Exchange Online:

1. Go to Reports tab on the top pane.
2. Navigate to Exchange Online → Exchange Online → Mailbox Reports → Size Reports.
   Note:
   Mailbox Size Changes Report is available under Exchange Online → Other Services → Security Reports → Admin Activities Reports.
   Shared Mailbox Size Report is available under Exchange Online → Exchange Online → Other Exchange Reports → Shared Mailbox Reports.
3. Choose a report from the set of reports available.
4. Enter the name of the Office 365 tenant.
5. Enter the other inputs required such as Mailbox Name, Size Restrictions, Period of report or Domain name.
6. Click on Generate Now.

This is how Exchange Reporter Plus helps you to monitor mailbox size related aspects. You can also download these reports as PDF, CSV, HTML, and XLS. Click here, to know more about how Exchange Reporter Plus simplifies Office 365 operations.