Answer: To view a user mailbox size in Exchange Server 2010 we can use either the EMC or Exchange Shell.
To view a user mailbox size using the GUI follow the steps below:
Open Exchange EMC -> Recipient Configuration -> Mailbox ->
Double click on the user name.
In the General tab you can see the User’s mailbox information including Size, number of items, mailbox database and more.
To view a user mailbox size using PowerShell follow the steps below:
The cmdlet below lists all the available options to view a user, database or server statistics.
If you just need to view a user mailbox size use this cmdlet:
Get-mailboxstatistics –identity ‘test1’
Get-mailboxstatistics –server srv2010mbx
Get-mailboxstatistics –database ‘db02’
Get-mailboxstatistics –identity ‘test1’
To get specific fields about the storage you can run this cmdlt.
Get-mailboxstatistics –database ‘corporate users’ |ft displayname, itemcount, storagelimitstatus -autosize
Update : Due to the popularity of this Post I decided to make a video on how to do it: