Your Free Pregnancy Due Date Calculator

When you first find out you are pregnant, you’ll naturally be curious as to when you are due. Using a pregnancy due date calculator is probably the easiest way to go about finding out, but it can also be figured out with some simple math.

Here is information on how a due date is calculated and problems that can arise from irregular cycles.

First you should understand how a typical pregnancy gestation is calculated. Human pregnancies are 40 weeks and it is calculated from a woman’s last menstrual period. This is 280 days and since it is an estimate, it can be off by two weeks in either direction.

This method of calculating a due date is fairly accurate for women who have regular 28 day cycles because those women will usually ovulate around day 14 of their cycle. This means their due date will be accurate to within a day or two.

However, not all women ovulate on day 14 and therefore their calculated due date can be off by weeks. For women who have short or long cycles, it is important to know the day of ovulation in order to get an accurate due date.

If it’s not known, an estimate can be made by subtracting 12 to 14 days from the normal length of the cycle. So, if a woman is having regular 38 day cycles, she can guess that she’s ovulating around day 24-26. From that date, she can add 38 weeks to get an estimated due date.

If you have a regular 28 day cycle, you can use Naegele’s rule to get a quick estimate of your due date. Simply take the date of your last menstrual period and add 9 months and 7 days. It is a rough guess, but it is much simpler and can be calculated in your head.

So, if all these numbers and calculations have you completely confused, simply use a pregnancy due date calculator and take out all of the guesswork. And remember, due dates are only estimates, so don’t be alarmed if baby comes earlier or later than this date.