The Estimated Due Date Calculator helps you with an appropriate estimate of the delivery of your baby. The human gestation period is the same for everyone. It takes about 37 to 40 weeks (around 280 days) from the day of conception until the day of delivery.
The method utilized here is simple counting from the first day of your last period. For women with an average length of menstrual cycle, that day is usually about two weeks before conception, which explains why pregnancies are expected to last for 40 weeks. This method does not take into account how long your period actually is or when you think you might have conceived.
Only one in 20 women deliver on her due date. You are just as likely to go into labor any day during the two weeks before or after the estimated date. A talk with the healthcare provider will help you more.