Code:

{ 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;

Code:

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;

Code:

function CalculateAge(Birthday, CurrentDate: TDate): Integer;

var

Month, Day, Year, CurrentYear, CurrentMonth, CurrentDay: Word;

begin

DecodeDate(Birthday, Year, Month, Day);

DecodeDate(CurrentDate, CurrentYear, CurrentMonth, CurrentDay);

if (Year = CurrentYear) and (Month = CurrentMonth) and (Day = CurrentDay) then

begin

   Result := 0;

end

else

begin

   Result := CurrentYear - Year;

   if (Month > CurrentMonth) then

     Dec(Result)

   else

   begin

     if Month = CurrentMonth then

       if (Day > CurrentDay) then

         Dec(Result);

   end;

end;

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

Label1.Caption := Format('Your age is %d',

   [CalculateAge(StrToDate('01.01.1903'), Date)]);

end;

Code:

DecodeDate(DM.Table.FieldByName('Born').AsDateTime, Year, Month, Day); // Дата рождения

DecodeDate(Date, YYYY, MM, DD); // Текущая дата

if (MM >= Month) and (DD >= Day) then

Edit2.Text := IntToStr((YYYY - Year))

else

Edit2.Text := IntToStr((YYYY - Year) - 1);