Option Explicit
Sub HeureMinDec()
Dim Rng As Range, T(), L&, C%, X#
Set Rng = Selection
T = Rng.Value
For L = 1 To UBound(T, 1)
For C = 1 To UBound(T, 2)
If Not IsEmpty(T(L, C)) Then
X = T(L, C)
T(L, C) = (Int(X) + (X - Int(X)) * 1.66666666666667) / 24
End If: Next C, L
Rng.Value = T
Rng.NumberFormat = "[h]:mm"
End Sub