Pregnancy Calculator: How to Compute Estimated Due Date and Date of Conception

Congratulations on becoming pregnant! Are you curious about the exact date that you have conceived? How about your estimated due date? 

Most soon-to-be parents are both excited to know the exact date that they will welcome their little bundle of joy. However, is it possible to know the exact date of conception and due date using manual calculation? Read on to find out if you could easily predict when your little one will arrive in this world.

Knowing the date of conception

Human eggs could only wait between 12 to 24 hours after ovulation before the mature egg comes out as menstruation. Usually, people use the date of ovulation as the date of conception. Take note that the exact date of your conception is usually not known with in-vitro fertilization. Ultrasound could give you an estimate of the date that you have conceived, much like the estimation of the date of fertilization. 

While you could get pregnant on the day you had sex, you should know that sperm could live inside your reproductive organ for up to five days before ovulation. 

(Photo : unsplash/Brooke Lark)

See also: How soon will a pregnancy test read positive? 10 signs to look out for

Knowing the estimated due date

The estimated due date (EDD) is the date when you will welcome your baby into the world. To give an estimation of your due date, add 280 days from the first day of your last menstruation period (LMP). It is also equivalent to adding nine months and seven days from your LMP. 

With this method, the accuracy will depend on the actual date as recalled by the pregnant woman. If the woman has a regular 28 days cycle, her conception will occur on the 14th day of her cycle. Using this calculation, one could estimate an error of up to two weeks. 

With in-vitro fertilization, they usually add 266 days from the date of conception to know the EDD. 

See also: Dad bod: Dads experience bodily changes like moms after having children

Using ultrasound to know EDD

With ultrasound, they use the size of the fetus to know the gestational age. It is the time elapsed from the first day of LMP. 

(Photo : unsplash/Heather Mount)

Reverse due date calculator

To compute your EDD using the reverse style, subtract three months from the month of your LMP, then add one year and seven days. For example, you last had your period on May 1, 2020, by subtracting three months, you get February as the month of your EDD. Add one year and seven days, and you get February 8, 2021, as your EDD. 

See also: How to Prevent Peanut Allergy in Children? Eat Peanuts While Pregnant!

That explains the ways to know your EDD. However, if you have so little time, there are a lot of online pregnancy calculators that you could use. The American Pregnancy website gives you an estimate of your due date. 

You may input the first day of your LMP and the average length of your cycle or you may choose to input the estimated date of conception. Click the "Calculate!" and you will get your EDD, and the website will also give you an estimate of how many weeks you are into your pregnancy.