Count Mailboxes in your Exchange Organization.

For an Exchange administrator there are a lot of different situations in which they may need to know how many mailboxes are in the organization.  Fortunately this is made easy in Exchange Server 2010 with a few simple PowerShell commands.  

When planning Exchange Server migrations just have a quick look at how many mailboxes are hosted on each database in the organization. To achieve this we can simply pipe the Get-Mailbox cmdlet into Group-Object.

Count of Exchange mailboxes in your organization.

To count the mailboxes in your organization even if you have multiple server use this command to get the mailbox count in your organization. Below is the command and the result of a lab server.

(Get-Mailbox).count

Note: If your organization has over 1000 mailboxes you need to use "-resultsize unlimited" to get the full list of mailboxes. Command below.

(Get-Mailbox -resultsize unlimited).count

Mailboxes per Exchange mailbox server.

To get a count of mailboxes per Exchange mailbox server use the below command.

Get-Mailbox | Group-Object -Property:ServerName | Select-Object name,count

Mailboxes per Exchange mailbox database

To get a count of mailboxes per mailbox database use the below command.

Get-Mailbox | Group-Object -Property:Database | Select-Object name,count

If you want only one mailbox database count use the below.

Get-Mailbox -database "databasename" | Group-Object -Property:Database | Select-Object name,count

Count mailboxes with email address policy disabled.

As you can see the Group-Object command allows us to see a count of mailboxes based on different attributes or properties of the mailbox. For example a count of mailboxes that are and are not exempt from email address policies. Use the below command to see email address policy enabled and disbaled users.

All these helps for an Exchange administrator when migrating/upgrading an Exchange server from one version (starting from Exchange2007) to other/latest versions. Use this article to get the mailbox statistics and database quota.