Sub Convertir()
Dim t, i&, x$, mois$, jour$
With [A4].CurrentRegion.Columns(15).Resize(, 6)
t = .Value 'matrice, plus rapide
For i = 2 To UBound(t)
If IsDate(t(i, 1)) Then t(i, 1) = CDate(t(i, 1))
x = t(i, 2)
If x Like "##/##*" Then
mois = Left(x, 2): jour = Mid(x, 4, 2)
x = jour & "/" & mois & Mid(x, 6)
If IsDate(x) Then t(i, 2) = CDate(x): t(i, 3) = t(i, 2) - t(i, 1)
End If
x = t(i, 5)
If x Like "##/##*" Then
mois = Left(x, 2): jour = Mid(x, 4, 2)
x = jour & "/" & mois & Mid(x, 6)
If IsDate(x) Then t(i, 5) = CDate(x): t(i, 6) = t(i, 5) - t(i, 1)
End If
Next
.NumberFormat = "dd/mm/yyyy hh:mm:ss"
.Columns(3).NumberFormat = "[hh]:mm:ss"
.Columns(6).NumberFormat = "[hh]:mm:ss"
.Value = t 'restitution
End With
End Sub