Sub TotalVolume()

    Dim db As Database, t As TableDef, n As Integer
    Dim w As Long, h As Long, v As Long

    v =  0 
    Set db = CurrentDb
    For n =  0  To db.TableDefs.Count -  1 
        Set t = db.TableDefs(n)
        If t.Connect =  "" Then
            w = GetTableWidth(t)
            h = GetTableHeight(t)
            Debug.Print t.Name, w, h, w * h
            v = v + w * h
        End If
    Next
    Debug.Print " Total: ", v

End Sub

Private Function GetTableHeight(t As TableDef) As Long

    Dim db As Database, rs As Recordset

    Set db = CurrentDb
    Set rs = db.OpenRecordset(t.Name)
    If rs.BOF Then
        GetTableHeight =  0 
    Else
        rs.MoveLast
        GetTableHeight = rs.RecordCount
    End If
    rs.Close

End Function

Private Function GetTableWidth(t As TableDef) As Long

    Dim n As Integer, w As Long

    w =  0 
    For n =  0  To t.Fields.Count -  1 
        w = w + t.Fields(n).Size
    Next
    GetTableWidth = w

End Function