Function ColumnLetter()
Dim C As Integer, L As Integer
With ActiveCell
C = .Column
If C > 26 Then L = 2 Else L = 1
ColumnLetter = Left$(.Address(0, 0), L)
End With
End Function
sans macro :
=SI(COLONNE()<=26;'';CAR(64+ENT(COLONNE()/26)))&CAR(65+MOD(COLONNE()-1;26))
ou :
=GAUCHE(ADRESSE(LIGNE();COLONNE();4);(COLONNE()>26)+1)