Babies Online wants to make it easier for every woman to find out her baby’s due date prior to that first appointment, by offering both helpful information and our fantastic due date calculator which is free for you to use.

The first thing you need to know in order to use our due date calculator is the first day of your last menstrual cycle. It is very difficult to get an estimated due date, without an early ultrasound, even from your doctor, unless you know this date. Calculators take into account your last period and assume conception took place a week after that date. They then add nine months to that date to give you the estimated due date.

It is important to remember that these calculations are just estimates – you should not count on your baby coming on that day. Only about 20% of babies come on the actual due date that was calculated. The other 80% are split between coming before the estimated due date, and after. Since a pregnancy is considered full term at 37 weeks (3 weeks before the calculated due date) and is generally not considered to be dangerously overdue till after 42 weeks (2 weeks after the calculated due date), this early date gives you an estimated time span of when your baby will come.

As your pregnancy progresses and you have ultrasounds done to check your baby, it is possible that your doctor will update and change your due date at which to reflect the rate at which your babyhas grown, using measurements taken in the ultrasound. In most cases, this will only change a few days or a week in either direction.

After you get that positive result from your pregnancy test, knowing the date your baby should be born gives you something to focus on, and to look forward to for the months to come. It is likely that for many women, the next nine months will seem the longest nine months of her life. Have no fear though. Your baby will arrive, whether he makes an appearance on your calculated due date or surprises you on another date.