For counting the total number of items/emails in one folder in Outlook, you can easily change this folder’s properties to archive it.

1. In the Navigation Pane, right click the folder whose total number of items you will count, and select Properties from the right-clicking menu. See screenshot below:

2. In the opening Properties dialog box, please check the Show total number of items option, and click the OK button. See screenshot above:

And now the number of unread items beside the folder name is replaced with the total number of all items/emails. See screenshot:

Notes:
(1) After selecting the folder in Navigation Pane, the number of all emails and number of unread emails are also shown at the Status bar.
(2) This method can only show one folder’s total number of items/emails at a time. For showing the total numbers of items of all folders, please try below VBA.

For counting the total numbers of all items in all folders, please apply below VBA code in Outlook.

1. Press Alt + F11 keys simultaneously to open the Microsoft Visual Basic for Applications window.

2. Click Insert > Module, and then paste below VBA code into the new opening Module window.

VBA: Count/show total numbers of items/emails in all folders in Outlook

Sub ShowTotalInAllFolders()
Dim oStore As Outlook.Store
Dim oRoot As Outlook.Folder

On Error Resume Next

For Each oStore In Application.Session.Stores
Set oRoot = oStore.GetRootFolder
ShowTotalInFolders oRoot
Next
End Sub

Private Sub ShowTotalInFolders(ByVal Root As Outlook.Folder)
Dim oFolder As Outlook.Folder

On Error Resume Next

If Root.Folders.Count > 0 Then
For Each oFolder In Root.Folders
oFolder.ShowItemCount = olShowTotalItemCount
ShowTotalInFolders oFolder
Next
End If
End Sub

3. Press the F5 key or click the Run button to run this VBA.
And now the total number of items/emails in each folder is showing beside the folder name. See screenshot:

If you have Kutools for Outlook installed, you can quickly count the total number of all items/emails in each folder with its All Folders Show Total Number of Items feature. Please do as follows:

Click Kutools Plus > Show Number of Items > All Folders Show Total Number of Item.

And now the number of unread items behind each folder on the Navigation Pane is changed to the the total number of all items immediately. See screenshot:

All of above methods are talking about counting the total number of all emails in each folder. Have you ever thought of summing the numbers of item in each folder and returning a total number? This method will introduce Kutools for Outlook's Statistics feature to count the total number of all/multiple items in all folders.

1. Click Kutools Plus > Statistics. See screenshot:

2. Click the OK button directly in the first Statistic dialog box.
Note: By default all folders in all email accounts are selected. For counting total numbers in several/multiple folders, please check them only and click the OK button.

And now the second Statistic dialog box comes out, and you will get the total number of all items/emails in all folders of all email accounts configured in your Outlook. See screenshot:

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