when is my due date?

best answer
How is my due date calculated? Your due date is calculated by adding 280 days (40 weeks) to the first day of your last menstrual period (assuming a 28 day cycle). Note that your menstrual period and ovulation are counted as the first two weeks of pregnancy. If you deliver on your due date your baby is actually only 38 weeks old not 40. Your due date is only an estimate