Sub transpose()
Dim cel As Range
Dim a, d, mois, valeur As Integer
a = 1
d = 1
For Each cel In Range("A2:A" & Range("A" & Rows.Count).End(xlUp).Row)
For i = 1 To 12
valeur = cel.Offset(0, i).Value
mois = cel.Offset(-d, i).Value
With Sheets("result")
.Range("A" & i + a).Value = cel
.Range("B" & i + a).Value = mois
.Range("C" & i + a).Value = valeur
End With
Next i
d = d + 1
a = a + 12
Next
End Sub