Connaître le nombre de cellules fusionnées verticalement et/ou horizontalement

Function nblignes(zone As Range) As Byte
nblignes = zone.Rows.Count
End Function

Function nbcolonnes(zone As Range) As Byte
nbcolonnes = zone.Columns.Count
End Function

Sub test()
MsgBox "Nb de lignes : " & nblignes(Range("toto").MergeArea) & vbLf & _
    "Nb de colonnes : " & nbcolonnes(Range("toto").MergeArea)
End Sub

Option Explicit
Function nblignes(PlageNommee As String) As Byte
If Names(PlageNommee).RefersToRange.Rows.Count > 1 Then
    nblignes = Range(PlageNommee).Rows.Count
Else
    nblignes = Range(PlageNommee).MergeArea.Rows.Count
End If
End Function
Function nbcolonnes(PlageNommee As String) As Byte
If Names(PlageNommee).RefersToRange.Columns.Count > 1 Then
    nbcolonnes = Range(PlageNommee).Columns.Count
Else
    nbcolonnes = Range(PlageNommee).MergeArea.Columns.Count
End If
End Function
Sub test()
MsgBox "Nb de lignes : " & nblignes("toto") & vbLf & _
    "Nb de colonnes : " & nbcolonnes("toto")
End Sub

Public Function NbColumns(zone As Range) As Integer
NbColumns = zone.MergeArea.Columns.Count
End Function

Public Function NbRows(zone As Range) As Integer
NbRows = zone.MergeArea.Rows.Count
End Function