Age Calculation

Age Calculation examples are illustrated below.  The first method used the datediff function in the age calculations.  The second tutorial demonstrates the use of the date serial function.  Each example uses today's date - this can be easily switch to a field from you forms or tables.

Age Calculation Long Method

Private Sub Birth_Dte_AfterUpdate()
    Dim iyears As Integer
    Dim tmonth As Integer
    Dim Bmonth As Integer
'
    iyears = DateDiff("yyyy", "01/01/" & DatePart("yyyy", Me.Birth_Dte), _
    "01/01/" & DatePart("yyyy", Me.Todays_Date)) - 1

    tmonth = DatePart("m", Me.Todays_Date)
    Bmonth = DatePart("m", Me.Birth_Dte)
'
    Select Case tmonth
        Case Is > Bmonth
            iyears = iyears + 1
        Case Is = Bmonth
            If DatePart("d", Me.Birth_Dte) <= _
            DatePart("d", Me.Todays_Date) Then iyears = iyears + 1
    End Select
End Sub

VBA Age Calculation - Short Method Using Date Serial Visual Basic Function:

Function age(vb_Dte As Variant)
  Dim v_Age_Calc As Variant
  v_Age_Calc = DateDiff("yyyy", vb_Dte, Now)
  If Date < DateSerial(Year(Now), _
    Month(vB_Date), Day(vb_Dte)) Then v_Age_Calc = v_Age_Calc - 1
  age = CInt(v_Age_Calc)
End Function

Additional information on the Date Serial function can be found in a VBA Functions tutorial section.  You can also review details about the DateDiff function in the same section.