How To Calculate Your Due Date

One of the first questions you will have when you discover you are pregnant is when is the baby due? This is also the first question that friends and family members will ask when you tell them you are expecting. You don’t have to wait until you visit the doctor to find out. You can easily calculate your due date at home.

To calculate your due date, you will need to know the date of your last menstrual period.

If you don’t have any idea when you last had a period, or if your periods are very irregular, calculating the due date becomes even more difficult. On the other hand, if you were undergoing treatments for infertility, you may have an exact conception date and this will make calculating the due date easier.

If you don’t know when you got pregnant, your doctor may suggest an ultrasound to confirm the gestational age of your baby. Measuring the baby is most accurate for confirming the due date in the early weeks of pregnancy. as the baby grows, there can be some difficulty in getting an accurate date, since babies range in size from small to large.

A baby that will be born large may be mistakenly estimated as older than the actual gestational age. The same mistake can be made with a baby that will be born on the smaller side, making that baby appear younger than the gestational age. In the first seven or eight weeks of pregnancy, all babies are approximately the same size and this makes dating the pregnancy easier than it will be later in pregnancy.

Assuming you do know the date of your last menstrual period, calculating the due date is easy. Take the date of your last menstrual period and add nine months and seven days to that date. For example, if your last menstrual period was on November 1^st, adding nine months would bring you to August 1^st. then add seven days and you will arrive at a due date of August 8^th.

There are online calculating tools for estimating your due date. They work on the same basic principal as the formula above, but they can be fun. Some offer additional information such as the estimated conception date. For this information, you will be asked to enter the length of your typical cycle. The reason for this is that ovulation generally occurs fourteen days before the date of your next menstrual period. For a 28 day cycle, this would be on day 14. For a 30 day cycle, it would be on day 16.

There are many tools online to calculate your due date. Keep in mind that a due date is just an estimate. It is not a magic day. Only about five percent of babies are actually born on the due date. This means there is a ninety five percent chance that your baby will not be born on that date. Most babies are born in a range of two weeks either before or after the date. For this reason, some women tell others they are due in “mid January” rather than the exact date to avoid constant phone calls on and around the due date.