Public Sub numCells()
Dim I As Integer
Dim K As Integer
Dim numCells As Long
For K = 1 To Workbooks.Count 'Loop through workbooks
Workbooks(K).Activate
For I = 1 To Worksheets.Count 'Loop through worksheets
numCells = numCells + Worksheets(I).UsedRange.Count
Next I
Next K
MsgBox (numCells)
End Sub