{ BrthDate:  Date of birth }
function TFFuncs.CalcAge(brthdate: TDateTime): Integer;
var
  month, day, year, bmonth, bday, byear: word;
begin
  DecodeDate(BrthDate, byear, bmonth, bday);
  if bmonth = 0 then
    result := 0
  else
  begin
    DecodeDate(Date, year, month, day);
    result := year - byear;
  if (100  month + day) < (100   bmonth + bday) then
    result := result - 1;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  Month, Day, Year, CurrentMonth, CurrentDay, CurrentYear: word;
  Age: integer;
begin
  DecodeDate(DateTimePicker1.Date, Year, Month, Day);
  DecodeDate(Date, CurrentYear, CurrentMonth, CurrentDay);
  if (Year = CurrentYear) and (Month = CurrentMonth) and (Day = CurrentDay) then
    Age := 0
  else
  begin
    Age := CurrentYear - Year;
    if (Month > CurrentMonth) then
      dec(Age)
    else
      if Month = CurrentMonth then
        if (Day > CurrentDay) then
          dec(Age);
  end;
  Label1.Caption := IntToStr(Age);
end;

{ BrthDate:  Date of birth }
function TFFuncs.CalcAge(brthdate: TDateTime): Integer;
var
  month, day, year, bmonth, bday, byear: word;
begin
  DecodeDate(BrthDate, byear, bmonth, bday);
  if bmonth = 0 then
    result := 0
  else
  begin
    DecodeDate(Date, year, month, day);
    result := year - byear;
  if (100  month + day) < (100   bmonth + bday) then
    result := result - 1;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
var
  Month, Day, Year, CurrentMonth, CurrentDay, CurrentYear: word;
  Age: integer;
begin
  DecodeDate(DateTimePicker1.Date, Year, Month, Day);
  DecodeDate(Date, CurrentYear, CurrentMonth, CurrentDay);
  if (Year = CurrentYear) and (Month = CurrentMonth) and (Day = CurrentDay) then
    Age := 0
  else
  begin
    Age := CurrentYear - Year;
    if (Month > CurrentMonth) then
      dec(Age)
    else
      if Month = CurrentMonth then
        if (Day > CurrentDay) then
          dec(Age);
  end;
  Label1.Caption := IntToStr(Age);
end;

procedure CariUmur(tglLahir:TDate; out tahun, bulan, hari:word);
begin
  tahun:=YearsBetween(today, tglLahir);
  if (DayOf(today) = DayOf(tglLahir)) and (MonthOf(today) = MonthOf(tglLahir))
    and (YearOf(tglLahir) <> YearOf(today)) then
    inc(tahun);
  tglLahir:=IncYear(tglLahir, tahun);
  bulan:=MonthsBetween(today, tglLahir);
  tglLahir:=IncMonth(tglLahir, bulan);
  hari:=DaysBetween(today, tglLahir);
end;