Bonjour,
Private Sub Worksheet_Change(ByVal Target As Range)
valeur As String, i As Integer
If Target.Address = "$B$3" Then
For i = 1 To Len(Target)
If Asc(Mid(Target, i, 1)) >= 65 And Asc(Mid(Target, i, 1)) <= 90 Then
valeur = valeur & Mid(Target, i, 1)
Else
valeur = valeur & Chr(Asc(Mid(Target, i, 1)) - 32)
End If
Next
Application.EnableEvents = False
Target = valeur
Application.EnableEvents = True
End If
End Sub