Calculer l'age de la personne a partir de la date de naissance-

Function Age(Date_nais)
    Dim Ans As Long, Mois As Long, Jours As Long
    Dim DNais As Date
    
    DNais = Replace(Date_nais, ".", "/")        'date au format "normal"
    Ans = (Year(Now()) - Year(DNais))          'nombre annees
    Mois = (Month(Now()) - Month(DNais))    'nombre de mois
    Jours = (Day(Now()) - Day(DNais))          'nombre de jours
    If (Ans > 0 And Mois > 0) Or (Ans > 0 And Mois = 0 And Jours >= 0) Then
        Age = Ans
    Else
        Age = Ans - 1
    End If
End Function

Private Function Age(DateDeNaissance As Date) As Integer
  Age = Int(Application.WorksheetFunction.YearFrac(DateDeNaissance, Now))
End Function

Function Age(Date_nais)
    DNais = CDate(Replace(Date_nais, ".", "/"))        'date au format "normal"
    Age = Int(Application.WorksheetFunction.YearFrac(DNais, Now))
End Function