j'ai trouvé je met le code au cas ou ça interresserait quelqu'un
Sub calcule()
ValeurCherchee = "---- ON ----"
Application.ScreenUpdating = False
Cpte = 0
For Each sH In Worksheets
Sheets(sH.Name).Select
With ActiveWorkbook.Worksheets(sH.Name).Cells
Set Sch = .Find(CStr(ValeurCherchee), LookIn:=xlValues)
If Not Sch Is Nothing Then
firstAddress = Sch.Address
Do
Set Sch = .FindNext(Sch)
Cpte = Cpte + 1
Loop While Not Sch Is Nothing And Sch.Address <> firstAddress
End If
End With
Next sH
Application.ScreenUpdating = True
MsgBox Cpte
End Sub