How to: Calculate Age

Microsoft Access does not include a function that will calculate the age of a person or thing based on a given date. This topic contains Microsoft Visual Basic for Applications (VBA) code for two custom functions, Age and AgeMonths, that will calculate age based on a given date.

The following function calculates age in years from a given date to today's date.

    Function Age (varBirthDate As Variant) As Integer
       Dim varAge As Variant

      If IsNull(varBirthdate) then Age = 0: Exit Function

      varAge = DateDiff("yyyy", varBirthDate, Now)
      If Date < DateSerial(Year(Now), Month(varBirthDate), _
                           Day(varBirthDate)) Then
         varAge = varAge - 1
      End If
      Age = CInt(varAge)
    End Function

The following function calculates the number of months that have transpired since the last month supplied by the given date. If the given date is a birthday, the function returns the number of months since the last birthday.

    Function AgeMonths(ByVal StartDate As String) As Integer
      Dim tAge As Double
      tAge = (DateDiff("m", StartDate, Now))
      If (DatePart("d", StartDate) > DatePart("d", Now)) Then
          tAge = tAge - 1
      End If

      If tAge < 0 Then
         tAge = tAge + 1
      End If

      AgeMonths = CInt(tAge Mod 12)

    End Function