In Outlook 2007, the Inbox and other folders by default displays the total number of unread items in folder. You can modify the folder settings to display the total number of items instead of only displaying the unread items alone. Listed below are the steps to display total number of items for folders in Outlook 2013, Outlook 2010 and Outlook 2007.
Click on the required folder (for example Inbox), right click and select properties
This would display the Inbox properties window. Select the radio option “Show total number of items” and click on the OK button.
This would display the total number of items in the Inbox. This can be done for any outlook folders.