One of the biggest obstacles to natural birth is misunderstanding your "due date." A due date does not mean there is only one safe day for your baby to be born. It is meant to establish a range of time that your baby is mature and safe to be born. Because modern obstetrics narrows this to a specific day, unnecessary interventions, like inducing labor A due date estimator is just that: a tool to help you estimate when your baby maybe due. The fact is that no amount of technology can - nor will - predict when your baby will enter this world.
However, we certainly understand that, the first thing any woman wants to do after finding out that she is pregnant, is to use a due date estimator. It is fun to count down the weeks as we fix our gaze on the "magical due date" - which for most women comes and goes with no baby.
In the United States, a pregnancy is based on 10 lunar months which is 280 days or 40 weeks. A pregnancy, however, is first considered term at 37 weeks: so a baby born at - or after - that time, will not be considered pre-mature - early. However, you may not know that all countries do not calculate a due date the same way. In France, for example, a due date calculator for pregnancy is based on 41 weeks. This is done because most babies will be born between 40 and 41 weeks. Remember, not all women are the same. You are a unique individual and so is your baby. And your baby will come when he or she is ready.
Therefore, as we mentioned, a baby is considered at "term" between 37 and 42 weeks gestation. The due date is simply the estimate of 40 weeks (the midpoint in that 4-5 week stretch). So if we think of being "due" as a period of time rather than a specific date, then a woman is not "overdue" once the due date has passed -- she has just simply reached the halfway mark in her due month!