My husband and I already have one child, a son we call Frumpkin.  We love him, but we’re thinking about giving him a little sibling.  We’ve set nothing in stone, my husband and I, but I admit that I’m having fun with the planning process.  Back to the internet due date calculator!

I tested several online due date calculators with my DS’s information (from back in 2012) to see which websites agreed
with my doctor’s due date and ranked them in order of most to least helpfulness.

Due Date Calculator

http://www.perinatology.com/calculators/Due-Date.htm

They include not only the usual first-day-of-last-menstrual-period option but options for conception date, date of 3-day embryo transfer, date of 5-day embryo transfer and a due date by sonogram!  And then they go on to list not only your estimated due date but the gestational age, date of conception, first fetal heart tones, and at least ten other time sensitive dates that you as a pregnant woman might need to know!  Super cool!

http://www.babycenter.com/pregnancy-due-date-calculator

Babycenter.com. They calculated my due date one day early, November 23^rd, but I’m hardly going to hold it against them.  They then give me a little message that my baby’s due date has passed and invite me to follow links to their ‘baby, toddler, preschooler, or big kid’ pages.  So they were super helpful!

http://www.firstresponse.com/due-date-calculator.asp?gclid=CKf11bmnxrkCFe9aMgodJmAAbg

I used their test to find out I was pregnant!  Their estimated due date agreed with that of my doctor.

http://www.webmd.com/baby/healthtool-due-date-calculator

Bare bones and a day early.  Meh.

http://www.thebump.com/calculators/duedate.aspx?MsdVisit=1

I’ve used the bump before, but I suppose that since I don’t still use it I probably I failed to find it personally relevant.  The calculator was a day earlier than my doctor’s prediction and the blurbs surrounding the calculator itself are reflections of questions other women might ask upon finding out they are pregnant; i.e. ‘when should I see the doctor?’ but are in no way personalized to me as the babycenter.com site did.

http://www.marchofdimes.com/pregnancy/calculating-your-due-date.aspx

You’d think the March of Dimes would have an accurate online due date calculator, but I think somebody needs to improve it.  I understand that it might be strange to ask what your due date is when you’ve already had your child but at least give an answer if you provide the option.  Don’t go out of your way to provide an irritating error message!  Humor the crazy lady!

http://www.whattoexpect.com/due-date-calculator/

A great site and it was on track with my doctor’s estimation as well. They also offer cool tips depending on how far along you are in your pregnancy.