Option Explicit
Function CptLettre(ByVal Col As String, ByVal s As String) As Long
Dim LastRow As Long, NbRows As Long
Dim i As Long, Cpt As Long
Application.Volatile
NbRows = Range(Col & ":" & Col).Rows.Count
LastRow = Range(Col & NbRows).End(xlUp).Row
For i = 1 To LastRow
If Range(Col & i) = s Then Cpt = Cpt + 1
Next i
CptLettre = Cpt
End Function